The richest people in the world have a staggering amount of wealth comparable to the GDP of small countries for some. Many of the worlds richest, like Microsoft founderBill Gates, Amazon CEOJeff Bezosor Facebook co-founderMark Zuckerberg, are self-made and turned an idea into a billion-dollar fortune. For others, like theKoch brothersof Koch Industries, their businesses were inherited, but their control of the company led to overwhelming amounts of wealth.

Many billionaires donate a large percentage of their money to charity. In fact, several of the worlds richest including Gates and Warren Buffet have madeThe Giving Pledge,which means they have vowed to give away at least half of their wealth to charity.

There are more than 2,200 billionaires in the world,Forbesreported, and that number is only expected to grow. Based on the most recent estimates fromForbes, the worlds richest people range from tech CEOs to heiresses to expert investors. Read on to find out how and why these people got so rich.

Amazon founder Jeff Bezos surpassed Bill Gates in July 2017 to become not only the worlds richest man, but therichest person in the worldwith an estimated net worth of $112 billion, according toForbess 2018 Billionaires List.

Bezoss fortune jumped in 2017 amid a remarkable year for the retail giant, in which the company bought Whole Foods in June 2017 and had a record-breaking Amazon Prime Day.

Bezos, who bought The WashingtonPostin 2013 for $250 million, owns about 17% of , which is part of what buoyed him to the worlds richest man. Morgan Stanley analysts predicted the company wouldsoon be worth $1 trillion, and Bezos himself earned $20 million in the last year.

Following the death of French heiress Liliane Bettencourt of LOral fortune in 2017, two women are now considered as the richest women in the world. One is Walmart heiressAlice Walton, who has a net worth of about $46 billion in March, according toForbes. And the other is Bettencourts daughterFrancoise Bettencourt Meyers, the 64-year-old heiress who now has a net worth of $42.2 billion, according toForbes.

Walton is the only daughter of Walmart founder Sam Walton. The heiress has not been heavily involved in the family business, but is an active art patron who opened the Crystal Bridges Museum of American Art in Bentonville, Ark., in 2011.

Though she rarely gives interviews or appears in front of the media, Bettencourts daughter is known as an academic and an avid pianist according toBloomberg.Bettencourt passed away at age 94 in September 2017 at a time when she was worth about $39.5 billion and among the top 20 richest people in the world overall, according toForbes. Her father, Eugene Schueller, founded the iconic cosmetics company LOral in 1907, and Bettencourt owned a third of the makeup brand with her children.

Responsible for the growth of online shopping and e-commerce, Jeff Bezos made his fortune by founding m. The 53-year-old CEO of Amazon, launched the retail giant in 1994 after leaving his New York hedge fund job. Initially an online book retailer operated out of Bezoss garage in Seattle, grew to become the worlds largest online shopping retailer, now worth over $430 billion,according to CNBC.

Bezos also owns a private space company Blue Origin and purchased The WashingtonPostin 2013 for $250 million. Amazon bought the upscale grocery chainWhole Foodsin June for an estimated $13.7 billion.

Bezoss parents, Jackie and Mike Bezos, operate theBezos Family Foundation, which supports youth education.

Born in Seattle, Gates used his first computer in 1967 while a kid in school. And about a decade later, he and his childhood friend Paul Allen, who also developed an interest in computers at their school, co-founded Microsoft together in 1975.

He was Microsofts CEO until 2000, and was the companys chairman and largest shareholder until 2014. Gates is still a member of the board and serves as a technology adviser for the company.

Gates and his wife, Melinda, co-chair the Bill and Melinda Gates Foundation, which is the worlds largest private charity. The foundation, launched in 1999, focuses on ending infectious diseases around the world, including HIV and malaria.

Outside of Microsoft, Gates is a public figure who, along with Warren Buffett and Mark Zuckerberg, founded The Giving Pledge to encourage other billionaires to donate a hefty amount of their wealth to charity. His charitable foundation focuses on health and development issues across the world.

An influential figure, the 61-year-old alsoreleases a listof his favorite books each year.

Berkshire Hathaway CEO Warren Buffett is an iconic figure and investment genius who bought his first stock when he was just 11 years old and filed his first taxes at age 13. Nicknamed the Oracle of Omaha, Buffett owns more than 60 companies.

One of the worlds best investors, Warren is also known for his cheap spending habits. In the recently released HBO documentaryBecoming Warren Buffett, the 86-year-old billionaire said he typicallypays under $4 for breakfastfrom McDonalds each morning.

Like his peers, Buffett is a philanthropist and has vowed to give away 99% of his wealth.

Bernard Arnault is responsible for many of the worlds most fashionable brands, including Bulgari, Louis Vuitton, Dom Perignon and Sephora. The French billionaire is the chairman and CEO of LVMH, which is the largest luxury goods company in the world.

The 68-year-old began his career as a civil engineer and gained control of his family parent company, Groupe Arnault. In the 1980s, he bought fashion brand Christian Dior a move that avoided bankruptcy for the brand.

Though he hasnt cracked the top 10 in several other rankings, Arnaults wealth grew by more than $5 billion in late April 2017 when he announced he would take full control of Christian Dior,Forbes reported.

Arnault is an art collector and created the Paris-based Foundation Louis Vuitton, which supports artistic creation in France.

Mark Zuckerberg was only a sophomore at Harvard University when he created the first version of Facebook in 2004. The social media powerhouse, which first began on college campuses, now has more than 1.2 billion users and dozens of offices located around the world. The company is now worth $400 billion.

Zuckerberg, the youngest of the worlds top billionaires at 33, is the chairman and CEO of Facebook in addition to being its co-founder. The 2011 award-winning filmThe Social Networkwas based off of Zuckerbergs founding of Facebook while in school, and the subsequent drama that came as a result.

Like other billionaires, Zuckerberg is a philanthropist who has donated millions to charitable causes. He and his wife, Priscilla Chan, have pledged to donate 99% of their wealth through the Chan Zuckerberg Initiative.

Amancio Ortega is a Spanish self-made billionaire best known for founding Inditex fashion group, which includes Zara clothing stores. The richest man in Europe, Ortega co-founded Inditex in 1975 with his ex-wife Rosalia Mera, who passed away in 2013.

Ortega, 81, is also the wealthiest retailer in the world and owns 59% of Inditex, which operates 7,000 stores worldwide. He stepped down as chairman of the company in 2011.

His approach to his companys success can be attributed to two factors: speed and customers. Oretgas fast fashion philosophy included refreshing the stock at Zara stores twice a week,CNBC reported. And instead of focusing on whats in at fashion shows, the company follows bloggers and customers for what theyre wearing to inform what is sold,Fortunereported.

Unlike other billionaires, Ortega has stayed out of the public eye. In fact, no photograph of him was ever published until 1999.

Mexican business tycoon Carlos Slim Hel is the richest person in Mexico, andowns more than 200 companiesin industries ranging from banking to retail to telecommunications. The 81-year-old owns America Movil, the largest mobile phone company in Latin America, as well as the Grupo Carso conglomerate company, which includes a host of retailers and restaurants, among other companies.

Slims father immigrated to Mexico from Lebanon with his family before Slim was born and had several successful retail and real estate businesses,Business Insiderreported. Slim inherited the businesses after his fathers death in 1953, and founded his his first company, insurance company Inversora Bursatil, after he graduated from college in the early 1960s.

His influence extends outside of Mexico as well. He now owns 17% of the New YorkTimes the largest individual shareholder of The Grey Lady.

Slim is a philanthropist, but has criticized other billionaires for giving their money to charity. Instead, Slimhas saidcompany leaders need to create companies rather than give away companies.

Charles Koch, 81, is the CEO, chairman and co-owner of Koch Industries, the second-largest private company in the United States.

Both he and his brother, 77-year-old David the companys executive vice president each own 42% of the conglomerate, which produces brands like Dixie Cup, Quilted Northern paper towels and Stainmaster carpet cleaner. The two brothers inherited the Wichita, Kansas-based company from their father.

The conservative Koch brothers use their deep pockets to influence politics and public policy through an expansive network. Koch-aligned networks like Americans for Prosperity gave rise to the libertarian movement, and the brothers have spent hundreds of millions backing politicians and influencing policy.

In fact, their network planned to spend $889 million just on the 2016 election, theNew YorkTimesreported. In 2012, the network spent under $400 million.

Larry Ellison, the founder, chairman and former CEO of software company Oracle, came from humble beginnings.

The 72-year-old billionaire founded his company in 1977, having never taken a computer science class in his life, according to theSmithsonian. He moved from Chicago to California after dropping out of college (twice), and worked several jobs where he learned about computer programming, including one where he helped build a database for the CIA.

He and two co-workers left the company to found Oracle, which became the worlds most popular database. He was the highest-paid executive in the United States before he stepped down as CEO in 2014, theWall Street Journalreported.

Ellison has already given millions to charity and education, and plans to give away billions.

But hes also spent his wealth in more luxurious ways as well. He has millions of dollars worth of real estate around the world, including the entire island of Lanai in Hawaii.

Michael Bloomberg wears many hats: CEO, philanthropist and politician.

In 1981, he launched Bloomberg L.P., an information technology and media company that has now grown to be worth $45 billion with more than 100 offices worldwide. He was a partner at Salomon Brothers, a Wall Street investment bank, before he started his own company.

As a philanthropist, Bloomberg has donated $5 billion of his wealth to contribute to certain causes that align with his political interests, including gun control and climate change.

And Bloomberg is an experienced politician. He served three terms as mayor of New York City from 2002 to 2013. During his tenure as mayor, he commuted to work at City Hall from his home on the Upper West Side by taking the New York City subway every day.

He also considered running as an independent in the 2016 presidential election, and has said he does not plan to run for the highest U.S. office in the future.

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