Here's a fun fact: New York City has more billionaires than any other city on the planet.

Last month, Forbes reported that 79 billionaires call the Big Apple home, besting Hong Kong, which has 68 members of the 10-digit-net-worth club, followed by Moscow with 60, Beijing with 51 and London with 48.

New York’s billionaires are worth a combined $364.6 billion, according to the magazine.

While many of NYC’s billionaires made their fortunes in finance and media, 11 of them built — or inherited — real estate empires, including Stephen Ross, Richard LeFrak, Donald Trump, Jerry Speyer, Leonard Stern, Sheldon Solow, John Catsimatidis, Jeff Sutton, Mortimer Zuckerman, David Walentas, Alexander Rovt and Leon Charney (who died last month). While their commercial holdings are well documented, their personal residences are less so.

This month, The Real Deal searched news reports and property records to map out where in Manhattan these billionaires rest their heads. While many of their homes were not publicly listed, below is a look at some of the most notable names and addresses we found.

SEE ALSO: Miami is a billionaire homebuyer's paradise — these are some of its most important luxury condos and mansions

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1. Michael Bloomberg

Net worth: $40 billion

17 East 79th Street

Former NYC Mayor Michael Bloomberg— founder of the Bloomberg media empire — made headlines in 2002 when he rebuffed the chance to live at Gracie Mansion in favor of his Beaux-Arts townhouse on 79th Street. He reportedly paid $3.5 million for the five-story limestone mansion in 1986 and over the years has quietly bought out neighboring units at 19 East 79th to expand his 12,500-square-foot abode. The mega-townhouse is one of more than a dozen homes Bloomberg reportedly owns around the world.

2. David Koch

Net worth: $39.6 billion

740 Park Avenue

David Koch — one half of the Koch brothers, the politically conservative pair that have bankrolled conservative politicians and causes nationwide — reportedly shelled out $18 million in 2004 for an 18-room duplex at 740 Park, the exclusive building that Ronald Lauder, Stephen Schwarzman and other business magnates call home. The pad, formerly owned by the Japanese government, underwent a two-year renovation by edgy architect Peter Marino before Koch moved in with his family.

3. Rupert Murdoch

Net worth: $10.6 billion

One Madison Avenue; 278 West 11th Street

In February 2014, after splitting up with his now-ex-wife Wendy Deng (and their penthouse at 834 Fifth), the News Corp. mogul shelled out $57.3 million for two units at One Madison: a three-bedroom condo on the 57th floor intended as guest quarters and a 6,800-square-foot triplex penthouse. Murdoch was reportedly living in the three-bedroom unit while the penthouse was under construction. But in April, he put the penthouse back on the market for $72 million. Murdoch also paid $25 million in 2014 for a Greek Revival townhouse on West 11th Street that he temporarily had on the market, asking $29 million, though it’s unclear if he or anyone else was living there.

The wealthiest 50 people in the world control a staggering portion of the world economy: $1.46 trillion — more than the annual GDP of Australia, Spain, or Mexico.

That's according to new data provided to Business Insider by Wealth-X, which conducts research on the super-wealthy. Wealth-X maintains a database of dossiers on more than 110,000 ultra-high-net-worth people, using a proprietary valuation model that takes into account each person's assets, then adjusts estimated net worth to account for currency-exchange rates, local taxes, savings rates, investment performance, and other factors.

Its latest ranking of the world's billionaires found that 29 of the top 50 hail from the US and nearly a quarter made their fortunes in tech. To crack this list, you'd need to have a net worth of at least $14.3 billion. And for the most part these people weren't born with a silver spoon. More than two-thirds are completely self-made, having built some of the world's most powerful companies, including Amazon, Berkshire Hathaway, Google, Nike, and Oracle.

From tech moguls and retail giants to heirs and heiresses, here are the billionaires with the deepest pockets around the globe.

SEE ALSO: The 20 most generous people in the world

DON'T MISS: The wealthiest people in the world under 35

49. TIE: Aliko Dangote

Net worth:$14.3 billion

Age: 58

Country: Nigeria

Industry: Diversified investments

Source of wealth: Self-made; Dangote Group

At 20, Nigerian businessman Aliko Dangote borrowed money from his uncle to start a business that dealt in commodities trading, cement, and building materials. He quickly expanded to import cars during the country's economic boom. Four years later, in 1981, he formed Dangote Group, an international conglomerate that now holds diversified interests that include food and beverages, plastics manufacturing, real estate, logistics, telecommunications, steel, oil, and gas. At $14.3 billion, Dangote's fortune is the largest in Africa and equal to 2.5% of Nigeria's GDP.

The majority of Dangote's wealth stems from his stake in Dangote Cement, which is publicly traded on the Nigerian Stock Exchange. He owns cement plants in Zambia, Senegal, Tanzania, and South Africa, and in 2011 invested $4 billion to build a facility on the Ivory Coast. Dangote bought back a majority stake in Dangote Flour Mills — which had grown unprofitable after he sold a large stake to South African food company Tiger Brands three years ago for $190 million — in December for just $1. He is also chairman of The Dangote Foundation, which focuses on education and health initiatives, including a $12,000-per-day feeding program.

49. TIE: James Simons

Net worth:$14.3 billion

Age: 77

Country: US

Industry: Hedge funds

Source of wealth: Self-made; Renaissance Technologies

Before revolutionizing the hedge fund industry with his mathematics-based approach, "Quant King" James Simons worked as a code breaker for the US Department of Defense during the Vietnam War, but was fired after criticizing the war in the press. He chaired the math department at Stony Brook University for a decade until leaving in 1978 to start a quantitative-trading firm. That firm, now called Renaissance Technologies, has more than $65 billion in assets under management among its many funds.

Simons has always dreamed big. About 10 years ago, he announced that he was starting a fund that he claimed would be able to handle $100 billion, about 10% of all assets managed by hedge funds at the time. That fund, Renaissance Institutional Equities Fund, never quite reached his aspirations — it currently handles about $10.5 billion— but his flagship Medallion fund is among the best-performing ever: It has generated a nearly 80% annualized return before fees since its inception in 1988.

In October, Renaissance shut down a $1 billion fund — one of its smaller ones — "due to a lack of investor interest." The firm's other funds, however, have been up and climbing. Simons retired in 2009, but remains chairman of the company.

47. TIE: Laurene Powell Jobs

Net worth:$14.4 billion

Age: 52

Country: US

Industry: Media

Source of wealth: Inheritance; Disney

The widow of Apple cofounder Steve Jobs, Laurene Powell Jobs inherited his wealth and assets, which included 5.5 million shares of Apple stock and a 7.3% stake in The Walt Disney Co., upon his death. Jobs' stake in Disney — which has nearly tripled in value since her husband's death in 2011 and comprises more than $12 billion of her net worth — makes her the company's largest individual shareholder.

Though she's best recognized through her iconic husband, Jobs has had a career of her own. She worked on Wall Street for Merrill Lynch and Goldman Sachs before earning her MBA at Stanford in 1991, after which she married her late husband and started organic-foods company Terravera. But she's been primarily preoccupied with philanthropic ventures, with a particular focus on education. In 1997, she founded College Track, an after-school program that helps low-income students prepare for and enroll in college, and in September she committed $50 million to a new project called XQ: The Super School Project, which aims to revamp the high-school curriculum and experience.

Last October, Jobs spoke out against "Steve Jobs," Aaron Sorkin's movie about her late husband that portrays him in a harsh light, calling it "fiction." Jobs had been against the project from the get-go, reportedly calling Leonardo DiCaprio and Christian Bale to ask them to decline roles in the film.

The richest people in the world climbed their way to the top of the fiscal food chain with business savvy, smart investments and dreams of making a meaningful impact on the world.

Find out how to become rich — and how to stay rich — with 10 inspiring tips from billionaires like Bill Gates and Warren Buffett.

SEE ALSO: Why you shouldn't quit your job to become a full-time entrepreneur

1. Bill Gates: Focus on development

Net Worth: $77 Billion

Microsoft founder Bill Gates has built a reputation for being not only the richest man in the world, but also one of the smartest and most serious thinkers alive today. So, it should come as no surprise that Gates got to where he is by focusing more on development and innovation and less on the business side of things.

In 2014, Gates told Rolling Stone, “You know, development sometimes is viewed as a project in which you give people things and nothing much happens, which is perfectly valid, but if you just focus on that, then you'd also have to say that venture capital is pretty stupid, too. Its hit rate is pathetic. But occasionally, you get successes, you fund a Google or something…."

2. Warren Buffett: Think long-term

Net Worth: $66 Billion

Self-made billionaire Warren Buffett believes in using long-term investment strategies. In fact, he accumulated most of his impressive wealth after turning 50 and continues to make smart investments to this day, pulling off what Forbes called his “biggest-ever deal” in August 2015.

Buffett once said, “Successful investing takes time, discipline and patience. No matter how great the talent or effort, some things just take time: You can’t produce a baby in one month by getting nine women pregnant.”

3. Jeff Bezos: Be a missionary to stay motivated 

Net Worth: $52.1 Billion

Amazon.com founder and CEO Jeff Bezos is a self-made billionaire and businessman whose many accomplishments include successfully launching a rocket into sub-orbit with his aerospace company, Blue Origin.

In a 2010 interview with Fortune, Bezos revealed that he thinks of business as a mission. “I strongly believe that missionaries make better products," he said. "They care more. For a missionary, it’s not just about the business. There has to be a business, and the business has to make sense, but that’s not why you do it. You do it because you have something meaningful that motivates you."

On a quiet, tree-lined block on the Upper East Side, 740 Park Avenue rises up: a legendary address, at one time considered (and, perhaps, still) the most important residential building in New York City.

The Art Deco co-op has been home to many of New York's most notable figures since it opened its doors in the 1930s. Today, it's still filled with the city's wealthiest residents — and prices just keep going up. The average listing price per square foot is currently $3,666.

Built in 1929 by the grandfather of Jacqueline Kennedy Onassis — who lived there as a child — 740 Park has just 31 residences, but they've commanded some of the highest real estate prices in New York history. John D. Rockefeller, financier Saul Steinberg, and Blackstone founder Steve Schwarzman have all hung their hats in the building. In fact, they've all lived in the very same apartment.

While some of New York's richest have decided to invest in the shiny new luxury condos available on "Billionaire's Row" on 57th Street or in downtown Tribeca's glossy high-rises, the Upper East Side still holds its own, according to Michael Gross, the author of "House of Outrageous Fortune" about 15 Central Park West and "740 Park: The Story of the World's Richest Apartment Building."

"I think in the current condo era, [740 Park] represents a previous generation of Manhattan wealth," Gross told Business Insider. "But I think that the cyclical nature of real estate makes it a very good bet that co-ops will have a comeback, and the east side will have a comeback."

There are currently four units with active listings in the building. If you buy in — and get past the co-op board — you'll have some very wealthy neighbors. Below, a roundup of those famous names.

Julie Zeveloff wrote an earlier version of this story.

SEE ALSO: These copper-clad luxury apartment buildings — complete with an amenity-filled skybridge — will gradually turn green over time

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740 Park opened its doors in October 1930, in the heart of the Great Depression. It remained a "financial sinkhole" until the 1980s, when apartment prices rose astronomically.

Source: "740 Park: The Story Of The World's Richest Apartment Building" by Michael Gross

These days, only the wealthiest types are even considered for admission to the co-op. Applicants must be able to show a liquid net worth of at least $100 million.

Source: "740 Park: The Story Of The World's Richest Apartment Building" by Michael Gross

But wealth isn't the only factor. Barbra Streisand, Neil Sedaka, junk bond tycoon Nelson Peltz, and the billionaire Leo Blavatnik have all reportedly been rejected by the co-op board.

Source: "740 Park: The Story Of The World's Richest Apartment Building" by Michael Gross

The wealthiest 50 people in the world control a staggering portion of the world economy: $1.46 trillion — more than the annual GDP of Australia, Spain, or Mexico.

That's according to new data provided to Business Insider by Wealth-X, which conducts research on the super-wealthy. Wealth-X maintains a database of dossiers on more than 110,000 ultra-high-net-worth people, using a proprietary valuation model that takes into account each person's assets, then adjusts estimated net worth to account for currency-exchange rates, local taxes, savings rates, investment performance, and other factors.

Its latest ranking of the world's billionaires found that 29 of the top 50 hail from the US and nearly a quarter made their fortunes in tech. To crack this list, you'd need to have a net worth of at least $14.3 billion. And for the most part these people weren't born with a silver spoon. More than two-thirds are completely self-made, having built some of the world's most powerful companies, including Amazon, Berkshire Hathaway, Google, Nike, and Oracle.

From tech moguls and retail giants to heirs and heiresses, here are the billionaires with the deepest pockets around the globe.

SEE ALSO: The 20 most generous people in the world

DON'T MISS: The wealthiest people in the world under 35

49. TIE: Aliko Dangote

Net worth:$14.3 billion

Age: 58

Country: Nigeria

Industry: Diversified investments

Source of wealth: Self-made; Dangote Group

At 20, Nigerian businessman Aliko Dangote borrowed money from his uncle to start a business that dealt in commodities trading, cement, and building materials. He quickly expanded to import cars during the country's economic boom. Four years later, in 1981, he formed Dangote Group, an international conglomerate that now holds diversified interests that include food and beverages, plastics manufacturing, real estate, logistics, telecommunications, steel, oil, and gas. At $14.3 billion, Dangote's fortune is the largest in Africa and equal to 2.5% of Nigeria's GDP.

The majority of Dangote's wealth stems from his stake in Dangote Cement, which is publicly traded on the Nigerian Stock Exchange. He owns cement plants in Zambia, Senegal, Tanzania, and South Africa, and in 2011 invested $4 billion to build a facility on the Ivory Coast. Dangote bought back a majority stake in Dangote Flour Mills — which had grown unprofitable after he sold a large stake to South African food company Tiger Brands three years ago for $190 million — in December for just $1. He is also chairman of The Dangote Foundation, which focuses on education and health initiatives, including a $12,000-per-day feeding program.

49. TIE: James Simons

Net worth:$14.3 billion

Age: 77

Country: US

Industry: Hedge funds

Source of wealth: Self-made; Renaissance Technologies

Before revolutionizing the hedge fund industry with his mathematics-based approach, "Quant King" James Simons worked as a code breaker for the US Department of Defense during the Vietnam War, but was fired after criticizing the war in the press. He chaired the math department at Stony Brook University for a decade until leaving in 1978 to start a quantitative-trading firm. That firm, now called Renaissance Technologies, has more than $65 billion in assets under management among its many funds.

Simons has always dreamed big. About 10 years ago, he announced that he was starting a fund that he claimed would be able to handle $100 billion, about 10% of all assets managed by hedge funds at the time. That fund, Renaissance Institutional Equities Fund, never quite reached his aspirations — it currently handles about $10.5 billion— but his flagship Medallion fund is among the best-performing ever: It has generated a nearly 80% annualized return before fees since its inception in 1988.

In October, Renaissance shut down a $1 billion fund — one of its smaller ones — "due to a lack of investor interest." The firm's other funds, however, have been up and climbing. Simons retired in 2009, but remains chairman of the company.

47. TIE: Laurene Powell Jobs

Net worth:$14.4 billion

Age: 52

Country: US

Industry: Media

Source of wealth: Inheritance; Disney

The widow of Apple cofounder Steve Jobs, Laurene Powell Jobs inherited his wealth and assets, which included 5.5 million shares of Apple stock and a 7.3% stake in The Walt Disney Co., upon his death. Jobs' stake in Disney — which has nearly tripled in value since her husband's death in 2011 and comprises more than $12 billion of her net worth — makes her the company's largest individual shareholder.

Though she's best recognized through her iconic husband, Jobs has had a career of her own. She worked on Wall Street for Merrill Lynch and Goldman Sachs before earning her MBA at Stanford in 1991, after which she married her late husband and started organic-foods company Terravera. But she's been primarily preoccupied with philanthropic ventures, with a particular focus on education. In 1997, she founded College Track, an after-school program that helps low-income students prepare for and enroll in college, and in September she committed $50 million to a new project called XQ: The Super School Project, which aims to revamp the high-school curriculum and experience.

Last October, Jobs spoke out against "Steve Jobs," Aaron Sorkin's movie about her late husband that portrays him in a harsh light, calling it "fiction." Jobs had been against the project from the get-go, reportedly calling Leonardo DiCaprio and Christian Bale to ask them to decline roles in the film.

Larry Ellison, Oracle's billionaire cofounder and current CTO, is famous for his brash personality.

He's shown time and time again that he's willing to go to great lengths to win, both in business and in his extracurricular activities. 

In honor of The America's Cup — one of Ellison's favorite hobbies, which begins Saturday in New York City — we've rounded up the stories that best show how competitive Ellison really is. 

SEE ALSO: The rise of Bill Gates, from Harvard dropout to richest man in the world

Ellison wants to be dominant in everything he does. On Oracle's competing with Microsoft to be the No. 1 software company, Ellison told 60 Minutes in 2004, "We're in second place. We're trying to catch them. They're not making it easy ... They have a monopoly. We don't. Darn it."

Source: 60 Minutes

Ellison obsessed over beating Microsoft's Bill Gates for years. Former Microsoft CTO Nathan Myhrvold told Vanity Fair in 1997: "I mean, the guy’s got six billion bucks. You'd think he wouldn’t be so dramatically obsessed that one guy in the Northwest is more successful. [With Larry] it’s just a mania."

Source: Vanity Fair

He led huge changes in the America's Cup sailing competition, moving away from standard catamarans to expensive, futuristic AC72s. The boats are 13 stories tall and reach speeds of up to 50 mph.

Source: Business Insider

What do the wealthiest people on this planet have in common? A great business sense? Luck? A strong work ethic? The likely answer is a combination of all of these and much more. However, when we look at the characteristics of successful entrepreneurs and investors, we tend to limit ourselves to typical business traits and disregard features like physical attributes or family life.

But what if these seemingly trivial aspects can give an indication of your potential to make billions? Take a look at GoCompare’s study of the top 100 billionaires over the last 20 years. At first glance some of the following traits may seem unrelated to making money, but they might just be the hidden key to becoming rich.

SEE ALSO: The 50 richest people on earth

1. Invest in your family

Are you married? Do you have three children? Statistically, you’re most likely to be a billionaire if your family looks something like this: Among the world’s richest, 87 percent are married and 63 percent have three of more children. 

Naturally, having a large family does not guarantee success, yet it seems that the emotional support family and marital life brings with it, might aid individuals in dealing with the stress and ambiguity of entrepreneurship.

2. No school of hard knocks

Although 14 percent of the 100 richest people in the world since 1992 have had no formal education at all or were college dropouts, attending certain universities and studying a few select subjects could increase your chance of making it big.

The most popular universities amongst the world’s billionaires are the famous elite institutions Harvard University and Stanford University, renowned for producing a league of influential entrepreneurs and world leaders. 

The most popular degrees cover a variety of sectors and include engineering, economics, computer science and business administration.

3. Successful star signs

Regardless of your opinion towards horoscopes and astrology, there is some evidence that certain star signs are linked to more successful people. Among the world’s top billionaires, 12.5 percent are Aquarius, who are said to be independent and inventive, traits that arguably come in useful for entrepreneurs.

On the other hand, the least represented star sign is Cancer, with only 5.9 percent of billionaires born between late June and July. Cancerians are linked to traits such as tenaciousness, but also tend to be insecure, a potential obstacle on the path to success.

Rich people think differently than the average person, and Apple cofounder Steve Jobs, who died with an estimated net worth of $10.2 billion, was no exception.

In a Quora thread answering the question "Do billionaires know something that normal people don't?" Patrick Methieson noted a Jobs quote that encapsulates the "billionaire mentality":

"Everything around you that you call life was made up by people that were no smarter than you and you can change it, you can influence it, you can build your own things that other people can use."

It's something that all wealthy people tend to internalize, explained Methieson, a venture investor who has worked with billionaires: "Billionaires realize that the world is pliable. With enough pressure applied to an endeavor, sufficiently resourceful people really can change the world. Contrast that with the rest of us who are more likely to assume the state of the world as static, or given."

Self-made millionaire Steve Siebold, who interviewed over 1,200 of the world's wealthiest people before writing "How Rich People Think," echoes this belief.

Rich people have an action mentality and are problem solvers. "While the masses are waiting to pick the right numbers and praying for prosperity, the great ones are solving problems,"he writes.

This doesn't mean they're smarter than the average person, as Jobs noted. "They are just more strategic," Siebold explains. "When the rich need money, they don't wonder if it's possible, they simply begin creating new ideas that solve problems."

And "the bigger the problem you solve, the more money you make," he says.

At the end of the day, getting rich is an inside job. "Let’s set the record straight once and for all: Anyone can become wealthy,"Siebold writes. "It has nothing to do with your education or where you come from. It's not what you do that guarantees wealth, it's what you are."

SEE ALSO: One quote from Donald Trump may help explain why he's a billionaire

DON'T MISS: The 50 richest people on earth

Join the conversation about this story »

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Greece has between 1,200 and 6,000 islands, according to a range of different estimates, and there is no definitive answer on how many the Greek government owns.

What we do know is that dozens of islands are up for sale and that for the country that is battling austerity measures and receiving a bailout from a number of international creditors — every cent counts.

On Private Islands Online, some islands are going for as little as €3 million (£2.1 million, $3.3 million). That's less than a house in an upmarket neighbourhood in London.

Over the last year, a number of islands have been sold via Private Islands Online but there are still a few up for grabs.

We checked out the islands that have visible price tags and ranked them by most expensive to the cheapest:

7. Dulichium Island — €40 million (£28.4 million, $44.1 million).

Location: Ionian Sea
Development: Non-developed
Size: 1,335.00 acres / 5.4 million square metres

This is the largest private island for sale in Greece right now. The highest point on the island is 250 metres above sea level. It has about 4,000 olive trees, shrubs, and dwarf bushes. It is undeveloped but presents an opportunity for someone to turn it into a luxury hotel resort.

6. Northern Aegean Island — €35 million (£25.9 million, $38.6 million).

Location: Chora
Development: Non-developed
Size: 86.00 acres / 348,029 square metres

This island is only half an hour away, by speedboat, from Athens. Numerous international developers are already showing an interest, according to Private Islands Online, because of the island's close proximity to the Greek capital.

5. St. Thomas — €15 million (£10.7 million, $16.5 million).

Location: Saronicos Gulf, near Corinth
Development: Non-developed
Size: 300.00 acres / 1.21 million square metres

St. Thomas Island is only 20 minutes away by water taxi from Corinth in Greece and only 45 minutes away from Athens. It is also part of the Diapori chain in the Saronicos Gulf, "an area of Greece mythologized for the lush emerald beauty of its picturesque islands."

As threatened, S&P has cut Icahn Enterprises (IEP), the investment firm controlled by billionaire Carl Icahn, to junk status.

The investment firm, which handles Icahn's own money, saw its unsecured debt rating fall from BB+ BBB-.

"The downgrade reflects IEP's elevated LTV ratio, which we now expect to remain between 45%-60% over the next 12 months," said S&P Global Ratings credit analyst Clayton Montgomery.

The agency said that most of Icahn's problems came from the deterioration of its portfolio (especially with positions like CVR Energy and Federal Mogul) and 

S&P warned that this may happen back in February.

Join the conversation about this story »

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Goldman Sachs CEO Lloyd Blankfein finally sold his Sagaponack, New York, estate, according to The Wall Street Journal.

First listed all the way back in 2007 for $14 million, the mansion has undergone a series of listings and price changes, the highest of which was $17 million in the summer of 2015.

The most recent listing was for $13 million, though it's not clear what the final selling price was.

In 2012, the CEO bought another house in Bridgehampton worth $32.5 million, which is reportedly the reason he elected to let go of this one.

Blankfein bought the property in 1995 and commissioned architect Larry Randolf and builders Men at Work to complete the mansion in 2001. The property has seven bedrooms, five full baths, a heated pool, and tennis courts, according to the listing.

Susan Breitenbach of the Corcoran Group handled the listing as of the sale.

Lucinda Shen contributed to an earlier version of this post.

SEE ALSO: Inside the enormous Hamptons mansion where celebrities like Beyonce and Jay Z regularly stay for $1 million a month

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Welcome to Lloyd Blankfein's summer home in Sagaponack, New York. Architects capped off the romantic estate with a barn-style roof.

The front doors open into a simple foyer. Light streams in from floor-to-ceiling windows on nearly every wall.

Take a seat in the summery, beige-and-cream-colored living room.

Everyone needs to take a vacation every once in a while, especially during the summer months.

But vacation means something a little different when you're a millionaire or even a billionaire.

From massive island retreats to private superyachts, these tech executives' second homes take luxury to the next level. 

SEE ALSO: This luxury appliance store lets you take a bath or cook a pizza before deciding to buy its products — and it could be the future of retail

When Microsoft billionaire Paul Allen isn't cruising the high seas on one of his yachts, he can relax at one of his many luxurious retreats.

In addition to an island in Washington and a beachfront Hawaiian estate, Allen owns a hilltop mansion on the Côte d'Azur, called the Villa Maryland. He employs a staff of 12 and counts Bono and Andrew Lloyd Webber as neighbors.

Source: Curbed

In October 2014, news surfaced that Facebook billionaire Mark Zuckerberg had bought a 750-acre property on the North Shore of Kauai. He reportedly paid more than $100 million for the estate, which includes a white-sand beach and former sugarcane plantation.

Source: Forbes

Salesforce CEO Marc Benioff loves all things Hawaii. He wears Hawaiian shirts to work and even named his dog "Koa," after a type of Hawaiian tree. He also owns a 5-acre estate on the Big Island, which he purchased for $12.5 million in 2000.

Source: Wall Street Journal, Honolulu Magazine

Gawker founder and CEO Nick Denton wrote an open letter on Thursday challenging the billionaire Silicon Valley investor Peter Thiel to a public debate on free speech.

The letter comes one day after Thiel's admission in a New York Times interview that he had secretly financed Hulk Hogan's high-profile lawsuit against the media company, which awarded Hogan $140 million in damages.

"The best regulation for speech, in a free society, is more speech," Denton wrote. "We each claim to respect independent journalism and liberty. We each have criticisms of the other's methods and objectives. Now you have revealed yourself, let us have an open and public debate."

"At the very least, it will improve public understanding of the interplay of media and power," he continued.

In The Times' interview, Thiel said that he had planned for years to back lawsuits against Gawker Media in an effort to shut it down because it "ruined people's lives for no reason."

Thiel acknowledged that he provided millions of dollars to Hogan's suit and other cases.

Denton's open letter, however, argues that the reporting done by Gawker — including the 2007 piece "Peter Thiel is totally gay, people,"— is newsworthy.

He said that the website serves to challenge powerful Silicon Valley figures, who until recently were "accustomed to dealing with acquiescent trade journalists and a dazzled mainstream media."

The news of Thiel's financial involvement in the Hogan suit has unsettled many in the media community who have called it an attack on press freedom. The concern is that the case could encourage other billionaires unhappy with specific news coverage to back lawsuits against media outlets.

"Peter, this is twisted. Even were you to succeed in bankrupting Gawker Media, the writers you dislike, and me, just think what it will mean," Denton wrote.

SEE ALSO: Mark Zuckerberg should put his money where his mouth is and throw Peter Thiel off Facebook's board

Join the conversation about this story »

NOW WATCH: Billionaire entrepreneur Peter Thiel explains precisely how Mark Zuckerberg changed the world

Some entrepreneurs who have made billions off of their tech ventures like to spend their fortunes in pretty extravagant ways, whether it be on private planes, summer homes, or even an entire island. 

Others turn to more-philanthropic efforts, choosing to donate their wealth to different causes through foundations and trusts. 

We've rounded up some of the most generous people in tech, all of which have decided to donate large portions of their wealth to charity rather than leave all of it to their children. 

SEE ALSO: These Instagram users show life from inside secretive North Korea

Tesla CEO Elon Musk

Musk may have five young boys from his first marriage — one set of twins and one set of triplets — but he's already donated much of his $12.9 billion fortune to renewable energy, science and engineering education, and pediatric health. 

He signed the Giving Pledge in 2012, committing to donate the majority of his wealth to charitable causes. He receives only $1 a year for his work with Tesla. 

Microsoft cofounder Bill Gates

Gates has been open about his decision not to leave his $84.9 billion fortune to his three children. They will reportedly inherit just a small slice, about $10 million each.

"I definitely think leaving kids massive amounts of money is not a favor to them,"he said in a Reddit AMA in February. 

He founded the Bill & Melinda Gates Foundation in 1994, and it currently has more than $36 billion in assets. Gates also teamed up with longtime friend Warren Buffett to start a campaign called "The Giving Pledge," which encourages other billionaires to donate at least half of their fortune to charity. 

Oracle founder Larry Ellison

Even with his lavish lifestyle, Larry Ellison has committed to giving away 95 percent of his wealth to charitable causes, especially to his medical foundation. 

"Warren Buffett personally asked me to write this letter because he said I would be 'setting an example' and 'influencing others' to give. I hope he's right," his letter to the Giving Pledge said in August 2010.

Despite committing the majority of his wealth to charity, he also gave his children Oracle stock when they were still babies (and the company was also young). Now that both the stock and company are worth a lot more, he is reported as to wanting to teach them charitable giving too. 

You could call them the most eligible bachelorettes in the world.

Five of the wealthiest women on earth are still unmarried, according to Wealth-X, a company that conducts research on the super-wealthy. With Valentine's Day in mind, it provided us with a list of the richest bachelorettes in five age groups: 20s, 30s, 40s, 50s, and 60s. Combined, they're worth $46 billion.

Meet five of the wealthiest in the world below, including owners of a biotech startup and a luxury-clothing business.

SEE ALSO: Out of the 50 richest people in the world, only 4 are women — here's why

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20s: India Rose James

Age: 24

Net worth: $280 million

Country: UK

India Rose James inherited an estimated 40% of her maternal grandfather Paul Raymond's $1 billion empire upon his death in 2008. His wealth — known as the Soho Estates—came from varied property investments in London's Soho district, establishing Britain's first adult-entertainment bar, and introducing pornography magazines to the country through Paul Raymond Publications.

James is currently focused on Soho Revue Gallery, the young artist-focused contemporary-art gallery she opened last spring with her then boyfriend Will Pelham. The socialite has breakfast at the family-owned Soho House every morning, enjoys traveling, and aspires to follow in her grandfather's footsteps to become "an entertainer."

30s: Elizabeth Holmes

Age: 32

Net worth: $4.5 billion

Country: US

Elizabeth Holmes is the youngest female billionaire in the world thanks to the success of her pain- and needle-free blood-testing company Theranos. When she was 19, Holmes dropped out of Stanford to found the company and has dedicated her life to it. According to a 2014 New Yorker profile, the CEO lives in a "two-bedroom condo in Palo Alto...no longer devotes time to novels or friends, doesn't date, doesn't own a television, and hasn't taken a vacation in ten years."

Though Holmes' image is that of a well-intentioned hard worker, she's facing harsh criticism for reports claiming dodgy business practices. "This is what happens when you work to change things," Holmes fired back. "First they think you're crazy, then they fight you, then you change the world."

40s: Filiz Sahenk

Age: 49

Net worth: $2.4 billion

Country: Turkey

Turkish billionaire Filiz Sahenk helms the luxury-brand clothing and tourism businesses of her late father's private conglomerate, Dogus Grubu. Sahenk oversees the company's retail partnerships with several global brands, including Emporio Armani, Gucci, and Loro Piana.

Despite being one of the most affluent women in Turkey, Sahenk isn't a public fixture. She's a behind-the-scenes advocate for women's leadership and development and an active philanthropist as president of the Ayhan Sahenk Foundation, which supports education, the environment, and social and healthcare-related causes. She also reportedly has a passion for collecting antique Turkish art.

Beijing has officially overtaken New York City as home to the most billionaires.

According to Hurun, a Shanghai firm that releases yearly rankings and research about the world's richest people, the Chinese capital has an even 100 billionaires in 2016, while the Big Apple has 95.

"Beijing took the title from New York after minting 32 new billionaires last year, while New York gained four," Gerry Shih of the Associated Press reports. "Rupert Hoogewerf, the founder of Hurun, attributed China's explosive wealth creation to Chinese market regulators allowing a flood of new initial public offerings after holding back new IPOs for several years."

Read on to see which other cities around the world made it on the "Hurun Global Rich List 2016."

SEE ALSO: How old 15 self-made billionaires were when they earned their first billion

20. New Delhi, India

Number of billionaires in 2015: 17

Number of billionaires in 2016: 20

19. Los Angeles, California

Number of billionaires in 2015: 22

Number of billionaires in 2016: 21

17. Bangkok, Thailand (TIE)

Number of billionaires in 2015: 27

Number of billionaires in 2016: 24

Recently, Bill Gates announced his plans to donate 100,000 chickens to people living in poverty as a way for cash-strapped families to start businesses.

Bolivia has said "No, thank you," adding that it resents the implication of the offer.

"How can he think we are living 500 years ago, in the middle of the jungle not knowing how to produce?" the Bolivian development minister, César Cocarico, told journalists at a press conference in La Paz on June 15. "Respectfully, he should stop talking about Bolivia."

Gates' proposal is part of a new partnership between the Gates Foundation and Heifer International, a charity focused on donating livestock to poor families around the world. Together, the two organizations plan to deliver chickens to citizens of countries in need as a way to lift them out of poverty.

"These chickens are multiplying on an ongoing basis, so there's no investment that has a return percentage anything like being able to breed chickens," Gates told reporters at a June 8 announcement of the partnership.

Although the exact list of countries is still undecided, Heifer International CEO Pierre Ferrari noted when the project was announced that there would be roughly a dozen nations involved — Bolivia included.

César Cocarico, however, has taken Bolivia's presence on the list as an insult. He argues that the country's sophisticated poultry market does not need a philanthropist's help. A local poultry producing association reports the country exports 36 million chickens annually and produces nearly 200 million in total.

The minister's complaint about the unwanted donation is a common one.

While billionaires might have noble causes like public health and global prosperity in mind, their efforts can easily veer into the realm of paternalism. Philanthropists sometimes assume that people in countries that don't live up to certain living standards are suffering, and rush in to save the day whether or not they're wanted.

Bolivia's economy is also getting significantly better. 

The country's GDP per capita in 2015 was three times higher than it was in 2006 — a jump from $1,200 to $3,119. The IMF predicts that Bolivia's economy will grow by 3.8% this year, which is the greatest gain projected for any country in South America.

That's impressive for a country that still sees 40% of its population living under the poverty line and, objectively speaking, is one of the poorest in the region.

What the nation could use is a round of applause. But free chickens? Maybe not.

Join the conversation about this story »

NOW WATCH: Bill Gates reveals why chickens are the answer to ending poverty

Li Ka-shing, the richest man in Hong Kong, is super concerned about Brexit — the possibility that the UK could leave the European Union after a closely contested referendum on Thursday.

Li said to Bloomberg:

"If Brexit happens, it will be detrimental to the UK and it will have a negative impact to the whole of Europe ... Of course I hope that the UK doesn’t leave the EU."

Li is the chairman of CK Hutchison Holdings Ltd., a company that has made him the 24th richest man in the world with a net worth of $28.6 billion, according to Bloomberg.

It's an energy, infrastructure, and telecom holding company that happens to derive 37% of its profit from customers in the UK. He also owns a real estate development firm.

Three months ago, Li said that he would pull money out of the UK if it left the EU. This is pretty significant, given that he has said that he wants to create the biggest mobile-phone carrier in the UK.

On Monday, billionaire investor George Soros, who famously shorted the British pound and "broke the Bank of England" back in the '90s, warned that Brexit could pull the pound down 20%.

SEE ALSO: Here's the simplest way to understand how a Brexit would affect the US

Join the conversation about this story »

NOW WATCH: Movie theater soda is a rip-off — but it's not the highest marked up item out there

Thirty years ago, Howard Schultz (No. 2 on the BI 100: The Creators) got into the coffee business with one goal in mind: to enhance the personal relationship between people and their coffee.

He's now responsible for Starbucks, one of the world's most beloved brands and the largest coffee chain on the planet. Last year, Starbucks' profits reached $2.8 billion on revenues of $19 billion, both record highs.

But Schultz isn't singularly focused on the traditional bottom line. He's a dynamic model of a progressive CEO who’s as animated by social issues and employee welfare as he is profit margins. Schultz has suggested that Starbucks’ creed — “to use our scale for good” — should be a model for other global corporations.

How did Schultz, who came from a "working poor" family in the Brooklyn projects, overcome adversity and grow a quaint Seattle coffeehouse into the largest coffee chain on Earth?

Scroll through to learn the story behind Starbucks and its leading man.

Additional reporting by Shana Lebowitz.

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Schultz was born on July 19, 1953, in Brooklyn, New York. In an interview with Bloomberg, he said growing up in the projects — "loosely described as the other side of the tracks"— exposed him to the world's wealth disparity.

Source:Bloomberg

He experienced poverty at an early age. When Schultz was 7 years old, his father broke his ankle while working as a truck driver picking up and delivering diapers. At the time, his father had no health insurance or worker's compensation, and the family was left with no income.

Source: "Pour Your Heart Into It"

In high school, Schultz played football and earned an athletic scholarship to Northern Michigan University. But by the time he started college, he decided he wasn't going to play football after all.

To pay for school, the communications major took out student loans and took up various jobs, including working as a bartender and even occasionally selling his blood.

Source: "Pour Your Heart Into It"

These wives of some of the world's most rich and famous men are no slouches.

Despite having access to all the money in the world, they have written novels, started companies, edited magazines, and practiced law.

In addition to their brains and entrepreneurship, many also happen to be gorgeous.

With ranks including the brilliant Amal Clooney and Mark Zuckerberg's pediatrician wife Priscilla, it's no wonder billionaires wanted to be with these incredible women.

Salma Hayek is married to Francois-Henri Pinault, the billionaire who runs Gucci, among other brands.

Why she's awesome: Hayek received an Oscar nomination for her role in the film "Frida" and has starred in numerous blockbusters.

She does philanthropy through Unicef, helping raise awareness for child vaccines. She has also advocated charitable causes, raising awareness for such issues as domestic violence and climate change.

Amal Alamuddin is married to actor and activist George Clooney.

Why she's awesome: Alamuddin is a highly accomplished human-rights lawyer whose clients include former Ukrainian Prime Minister Yulia Tymoshenko and the country of Armenia in its fight for recognition of the Armenian Genocide.

She's also got a killer sense of style.

Nita Ambani is married to industrialist Mukesh Ambani, the richest man in India.

Why she's awesome: Nita is co-owner of the Mumbai Indians cricket team and is actively involved in fundraising for education, disaster relief, and people who are blind.

In 2016, Forbes named her one of the world's most powerful female business leaders for her role in the Reliance empire.