Many of the world’s richest people came from humble backgrounds to become billionaires, with childhood poverty, war and other issues driving them on to succeed. Using the Forbes Billionaires List 2018 as a guide, and starting from the least rich to the richest, here are some of the wealthiest people on the plant who survived a challenging upbringing and went on to build huge billion-dollar empires.

Telecommunications genius and self-made billionaire Kenny Troutt has now retired but not before making a cool $1.4 billion (£1.09bn) fortune. An avid horse racing fan, Troutt owns WinStar Farm in Kentucky and is a breeder of Thoroughbreds. Troutt’s fortune also allowed him to sponsor his son's nationally-competitive basketball team for years and even provide them rides to tournaments on his private jet.

The son of a single mother who worked as a bartender, Troutt grew up in public housing in Mount Vernon, Illinois. What he lacked in funds he made up for in determination, paying his way through Southern Illinois University by selling insurance alongside studying.

In 1988 Kenny Troutt founded long-distance phone company Excel Communications and in 1996 Troutt took the company public. In 1998, Troutt sold Excel Communications to Teleglobe in a $3.5 billion (£2.7bn) deal and reinvested the profits in stocks, bonds and horses.

David Murdock, worth $2 billion (£1.56bn), is the chairman of privately-held Dole Food Products and Castle & Cooke. He owns residential and commercial properties in Arizona, California and Hawaii and a collection of Arabian horses. The 95-year-old has also donated heavily to longevity research and vows to live until he is 125.

Murdock, who is dyslexic, dropped out of high school in the ninth grade and worked at a gas station before being drafted into the Army in 1943. After serving in World War II, Murdock found himself homeless with little more than a dollar to his name.

After borrowing $900 from a good Samaritan he bought a diner in Detroit and flipped it for a tidy profit. He used the proceeds to buy a car, drive to Arizona and started Castle & Cooke, a real estate company that grew to include Dole Foods Co, a fresh fruit and vegetable producer.

John Paul DeJoria has a net worth of $2.5 billion (£1.95bn). He is the co-founder of hair-care company John Paul Mitchell Systems, which generates $1 billion (£770m) in annual revenue, as well as high-end tequila company Patrón Spirits, which sells more than two million cases each year. DeJoria doesn’t measure his success in terms of dollars though, his wealth makes him "feel really good to be financially blessed and give back."

When John Paul DeJoria was a child he sold Christmas cards and newspapers to support his family. But sadly it wasn’t enough and he was sent to foster care and wound up in a gang, before finding an olive branch in the form of the military.

For a while DeJoria slept in his car and sold shampoo door to door, before he teamed up with Paul Mitchell in 1980 and turned $700 into the hugely-successful John Paul Mitchell Systems. Not too long after their company took off, Mitchell died of cancer and DeJoria took over. In 1989 DeJoria and partner Martin Crowley acquired a stake in boutique tequila maker Patrón and have grown it to sales of more than $800 million (£624m).

EY World Entrepreneur of the Year 2015 and Montpellier rugby club president Mohed Altrad is worth $2.5 billion (£1.95bn). He heads up the $4 billion (£3.09bn) Altrad Group, which provides construction and maintenance services, but his start in life was worlds apart from this. Of his past he said: "I had no special dream – only the ambition not to accept my initial destiny."

Mohed Altrad came from humble beginnings, born an orphaned Bedouin in the Syrian desert. Raised by his grandmother, Altrad was banned from going to school, but an innate drive to learn saw him attending school anyway. He eventually won a scholarship to study in France despite speaking no French and having very little money.

In France, Altrad was poor and lived off one meal a day, yet managed to earn himself an undergraduate degrees in physics and math, and a Ph.D. in computer science. In 1985, after a short spell working for a tech firm and the Abu Dhabi National Oil Company, Altrad bought a bankrupt scaffolding manufacturer in France. With his partner he created the world's leading scaffolding company.

Howard Schultz is an American self-made billionaire, most famous for making coffee chain Starbucks the global success story that it is. He has a net worth of $2.7 billion (£2.1bn) and is the 887th richest person in the world. But his upbringing was anything but affluent.

Schultz was born in 1953 in Brooklyn, New York, and grew up in a public housing project. His father was a truck driver and the family were poor. Encouraged by his parents, Schultz got a place at Northern Michigan University via an athletic scholarship. He was the first person in his family to attend college. He worked as a bartender and even sold blood throughout college. After graduating he got a job in sales at Xerox and later became manager of US operations at Hammerplast.

By 1982 he became director of marketing for Starbucks and was then CEO from 1986-2000. Under his reign the company experienced an expansion of gargantuan proportions. To this day, Schultz is heralded as the person responsible for revolutionising the coffee shop industry. For Schultz, it was crucial to build a company with soul. Schultz said he “wanted to build the kind of company that my father never got a chance to work for, in which people were respected."

Media Mogul Oprah Winfrey, worth $2.9 billion (£2.27bn), is an American media executive, talk show host, actress, producer, and philanthropist. She has a large number of A-lister friends and an impressive number of mansions. Her 65-acre Californian estate is large enough for Winfrey to run a two-mile route without leaving the property.

Winfrey overcame a tough childhood, born to a teen mother in rural Mississippi and raised without indoor plumbing. Winfrey was determined to break away, earning herself a scholarship to Tennessee State University and becoming the first African American TV correspondent in the state at just 19. Winfrey then parlayed her role as a news anchor into a 25-year talk show gig.

Winfrey’s hit talk show has transitioned into a media and business empire, including a magazine and cable channel, OWN. Her 25.5% of the network is worth about $75 million (£58m) and Winfrey also owns an 8% stake in Weight Watchers, acting as their brand ambassador. Reinvested, the profits from her show add up to nearly $2 billion (£1.56bn). Read more about Oprah's incredible rags-to-riches story

Chinese billionaire businesswoman Zhang Xin has an estimated worth of $3.6 billion (£2.8bn) and has been called the ‘woman who built Beijing’ due to her groundbreaking career in property. But nothing was handed to Xin on a plate.

Born in Beijing in 1965, during the Cultural Revolution, Xin grew up with her mother after her parents divorced when she was five. Mother and daughter moved to Hong Kong when Xin was 14 and, to make ends meet, they both got jobs as factory workers. Xin was determined to learn however and would attend evening school after work. Aged 19, Xin flew to England to learn English at a language school in Oxford. She got a job at a fish and chip shop to stay afloat.

Xin went on to study at both Sussex and Cambridge universities before landing a job at Goldman Sachs, where she worked in floating Chinese factories on the public stock exchange. In 1995, Xin and her husband founded property development company SOHO China. To date, the company has developed over 60 million square feet of land.

Self-made investor Ken Langone is now worth $3.6 billion (£2.8bn). Langone is a philanthropist and in 1999 donated $10 million to NYU's part-time MBA programme and $200 million (£155m) to the university's medical centre in 2008. However, the 82-year-old has not forgotten his humble beginnings and still phones his electricity provider if he needs to challenge his bill.

The grandson of Italian immigrants, Langone's father was a plumber, and his mother ran an elementary school cafeteria. Langone dug ditches for the Long Island Expressway and his high school principal advised his parents not to waste their money sending the “unpromising” student to college. Thankfully they disagreed and his parents mortgaged their house so that he could study economics at Bucknell University. Once there, Langone worked as a caddy, butcher and ditch digger to stay afloat.

After two years in the US Army, he made a name for himself on Wall Street, taking Ross Perot Sr.'s Electronic Data Systems public in 1968. In 1978, Langone co-founded US retail giant Home Depot with Arthur Blank and Bernard Marcus. All three are now billionaires.

Do Won and his wife Jin Sook Chang, co-founders behind the $4 billion (£3.12bn) fast fashion darling Forever 21, are worth $3 billion (£2.34bn). Family and faith are more important to the Changs than wealth. Their Ivy-league educated daughters, Linda and Esther, work alongside their mother in merchandising. They go to early morning prayer everyday and have the bible verse John 3:16 printed on the bottom of their company's shopping bags.

Before the couple founded the incredibly successful clothing empire, he struggled to make ends meet. The pair moved to the US from South Korea in 1981 with not much more than a high school education. Do Won worked three jobs simultaneously – in a coffee shop, as a gas station attendant and a janitor – to support his family.

In 1984, the Changs started the business in a 900-square-foot store in Los Angeles thanks to a mere $11,000 in savings. Capitalising on wholesale closeouts, they bought merchandise for cheap and hit $700,000 in first-year sales, prompting them to open a new store every six months. Forever 21 now has 790 stores spanning 48 countries.

Stephen Bisciotti has a net worth of $4.2 billion (£3.3bn). He is the co-founder of Allegis Group, the world's largest private staffing firm, although these days he is more well-known for being the majority owner of American football team the Baltimore Ravens of the NFL. The business mogul had to work hard to get where he is today though.

Born in Philadelphia in 1960, Bisciotti was the youngest of three children to parents Bernard and Patricia. The family moved to Baltimore when he was one. Tragedy struck when Bisciotti’s father died of leukemia when Stephen was eight, leaving Patricia to raise three kids on her own. Ever the grafter, Bisciotti had part-time jobs mowing lawns, babysitting and and pumping gas throughout his teens before going off to college at nearby Salisbury State University.

Aged 23, he started Aerotek in a basement office with his cousin and they raked in $1.5 million in the first year. The Allegis Group, which Aerotak is part of, is now a $10.8 billion (£8.5bn) company, with nearly 500 offices worldwide. Always an avid sports fan, in 2000 Bisciotti bought 49% ownership of the Baltimore Ravens.

Frank Lowy has a net worth of $5.8 billion (£4.6bn) and is the 296th richest person in the world. He is a renowned businessman, co-founding global giant Westfield Corporation, which has shopping centres in Australasia, the US, UK and Europe. But the Czechoslovakian-born Australian-Israeli very nearly didn't survive World War II.

Lowy was born in Slovakia, then Czechoslovakia, in 1930. When World War II broke out, Lowy’s family moved to Hungary to avoid being arrested by the Nazis. One day, Lowy’s father Hugo disappeared; Lowy would later find out that he had been taken to Auschwitz and killed. It wasn’t until 1952, after a stint in a detention camp in Cyprus and fighting in the 1948 Arab-Israeli War, that Lowy moved to Australia armed with one suitcase and no money.

In Australia, he reunited with his family and, in 1953, he met fellow immigrant John Saunders and together they started developing shopping centres across Australia and around the world. Lowy said: “Never give up! People don’t understand how persistent you have to be. You come up against an obstacle and you have to find a way of moving forward. You take detours, navigate between the obstacles and make it happen. Unless you are very strong and convinced you can succeed, you will be swept away."

Fashion designer Ralph Lauren has an estimated wealth of $6.2 billion (£4.9bn) and comes in at number 281 on the Forbes Billionaires List of 2018, making him one of the richest clothing moguls on the planet. But the founder of the preppy all-American clothing empire grew up in less than comfortable surroundings.

Lauren, the youngest of four siblings, was born and brought up in the Bronx, New York City, to Ashkenazi Jewish immigrants. His mother Frieda was an artist, his father Frank was a house painter and money was tight. Ralph Lauren’s surname was actually Lifshitz but he changed it to Lauren when he was 16 to avoid mispronunciations.

After dropping out of college and a stint in the army, Lauren started work as a sales assistant at Brooks Brothers department store. In 1967, he started making ties in a small office in New York and the Ralph Lauren Corporation was born. The business soon become something of an empire, its Polo line and fragrances selling millions worldwide and Ralph Lauren became one of the fashion world's most recognisable brands.

Instant messaging whizz Jan Koum is worth $9 billion (£7.02bn). In April 2018, Koum announced his impending departure from Facebook HQ in California, however he continues to work one day a month and banks close to half a billion dollars every financial quarter, stalling until his remaining stock options vest.

When Jan Koum moved to California from the Ukraine as a teen his family struggled to stay above the poverty line. Koum relied on food stamps and swept floors to make ends meet. Despite his tough upbringing, Koum worked hard at school. By the age of 18 Koum became interested in programming and enrolled at San Jose State University.

In 1997, Koum was hired by Yahoo! as an infrastructure engineer where he worked for nearly nine years before leaving aged 30 with enough cash to launch his own business. In 2009 Koum co-founded real-time messaging app WhatsApp. The app was so successful Facebook bought it for a massive $19 billion (£14.82bn) and Koum was invited to sit on the Facebook board.

Russian business tycoon Roman Abramovich is worth $11.3 billion (£8.81bn). He has donated more money than any other living Russian, giving away $2.5 billion (£1.9bn) to the Chukotka region. He is most likely to be seen on his yacht, Eclipse, which he bought for nearly $400 million (£309.5m) in 2010 and is the world's second-largest yacht, or cheering on Chelsea, the English soccer club he owns.

Abramovich spent his early life in a region far-removed from the riches of his current home in London’s Knightsbridge. Orphaned at a young age, he was raised by his grandparents in Komi, a dark region in Siberia. He dropped out of two colleges, yet his entrepreneurial spirit has seen him making money selling stolen gasoline, rubber ducks, perfumes and automotive parts, and from businesses ventures such as pig farming and bodyguard recruitment.

Abramovich became friends with one of his country’s most influential individuals and became a big player in top circles. His acquisition of the large oil company Sibneft created the vast majority of his wealth. In 2005 he sold the oil company for $13bn (£10.15bn).

Harold Hamm is the 100th richest person in the world and is worth $14.1 billion (£11.1bn), due to his lucrative company Continental Resources, which produces more than 200,000 barrels of oil a day and is known for pioneering horizontal drilling and hydraulic fracturing (better known as fracking) in the Bakken region of North Dakota.

Born in Lexington, Oklahoma in 1945, Hamm was the youngest of 13 children. His parents were cotton shareholders and the family were so poor that they had no indoor plumbing or electricity. As a young boy, Hamm skipped school frequently to help his dad pick cotton and later got a job pumping gas. He didn’t go to college. Instead, inspired by the surrounding oil in Oklahoma, he started reading up on geology, at the same time as launching his own trucking company.

In the early 70s he drilled a well and found oil. This was the beginning of his lifelong career in the business. The septuagenarian oil tycoon said: "It just grabbed my imagination that anybody could find this hidden, ancient wealth and it was yours." His career in oil has also seen him delve into American politics, landing him the role of national energy adviser to Mitt Romney’s presidential campaign in 2012.

Thomas Peterffy has a net worth of $20.3 billion (£15.9bn) and is the richest person in the state of Florida. He is the founder and CEO of Interactive Brokers, a leading securities firm boasting over $6 billion (£4.7bn) in equity capital. But Peterffy's story of success is nothing short of extraordinary.

Peterffy was born in Budapest, Hungary in 1944 in a hospital basement during a Russian air raid. In search of the American dream he emigrated to New York when he was 21 with no English and no money. Through hard work and perseverance he managed to get a job as an architectural draughtsman for an engineering firm and went on to programme computers there.

By the 1970s he had saved up enough money to buy a seat on the New York Stock Exchange, working on the electronic trading of securities. In 1993, he started Interactive Brokers and the company was so successful Peterffy became known as the father of digital trading.

Luxottica founder Leonardo Del Vecchio is one of the richest men in not just Italy but the entire world, worth $23.1 billion (£18.02bn). Yet the founder of one of the most powerful companies in the eyeglasses market rose from humble beginnings to make it to the top.

Born in Italy, Del Vecchio was one of five children. Sadly, because his family was so poor, Del Vecchio, along with his siblings, was sent to an orphanage. He later went to work gruelling shifts in a factory making moulds for eyeglass frames. He began apprenticing at a car and eyewear parts factory at age 14 to put himself through design school.

All Vecchio’s hard work and work experience paid off and at 25 he went on to open his own moulding shop. Luxottica eventually went on to become the world’s largest maker of sunglasses, owning Sunglass Hut, LensCrafters, Ray-Ban and Oakley and making glasses for virtually every brand, including Bulgari, Chanel and Armani.

French tycoon and luxury fashion brand founder Francois Pinault is worth an incredible $30.7 billion (£23.95bn). Pinault and his family own a 3,000-piece art collection, with works by Picasso, Mondrian and Koons, auction house Christie's, several vineyards, a French soccer club, a theatre in Paris and a luxury yacht and expedition company. In 2019 they plan to open a museum in France.

For someone who leads such a lavish lifestyle, you would not expect the fashion mogul to have been bullied for being poor at school. Pinault eventually dropped out, yet this didn’t affect his business smarts. In 1963 the Frenchman went on to start Kering (formerly PPR), which made wood and building materials.

In 1999 Pinault changed the direction of the business towards luxury goods when he bought a controlling stake in Gucci Group. Kering now owns fashion brands Saint Laurent, Alexander McQueen and Stella McCartney, to name a few. The group also owns sports brand PUMA and the $19 billion (£14.82bn) company is run by Pinault's son.

Nicknamed Superman, Li Ka-shing is revered as one of the most influential businessmen in Asia and he is certainly the richest, worth $33.1 billion (£25.82bn). In March 2018 Li announced plans to retire as chairman of CK Hutchison Holdings and CK Asset Holdings and his son Victor will take over the conglomerate, which now has 323,000 employees and operates in more than 50 nations.

Li hasn’t always been so blessed. At age 12, his family fled from China to Hong Kong and his father, a primary school principal-turned-watch factory worker, died shortly after. Li was forced him to leave school and work 16-hour days in a plastic factory to support his family. This gave him the drive to start his own company, Cheung Kong Industries, which manufactured plastics.

Cheung Kong Plastics, named after the Yangtze River, was started with $6,500 in savings and loans from relatives, but he eventually moved into real estate. His Li Ka Shing Foundation has donated more than $2.6 billion (£2bn), with over 80% going to the Greater China region.

Sheldon Adelson is at number 21 on the Forbes Billionaires List 2018 with a fortune of $38.5 billion (£30.2bn). As CEO of Las Vegas Sands Corporation, he made his money in creating dazzling casinos and hotels all over the world. Famously, he developed the Venetian, the Venice-themed resort hotel and casino in Nevada, which boasts a shopping mall with canals and singing gondolas, as well as over 4,000 rooms and 18 restaurants. But the billionaire’s early life was far from opulent.

Born in 1933, Adelson grew up in Dorchester, a notoriously rough part of Boston. His father was a taxi driver and his mother ran a knitting group. It seems Adelson was keen to build an empire from the get-go, as he started his first business when he was 12, when he borrowed $200 from his uncle to purchase a license to sell newspapers locally.

After a stint in the army and as a journalist, he became an entrepreneur and had various businesses, selling toiletry kits and running a charter tours business. In the late 1980s he started his casino business and began to make serious money. Like many business moguls, he has his fingers in lots of pies. The 85 year-old owns two newspapers and donated $25 million (£19.6m) to Donald Trump's 2016 presidential campaign, reportedly making him the largest single donor in the presidential election.

Oracle software company founder Larry Ellison is worth $58.5 billion (£45.9bn) and is the 10th richest person in the world. He owns numerous luxury houses, yachts and even purchased 98% of the Hawaiian island of Lanai for $300 million (£226m) in 2012.

Born Lawrence Joseph Ellison on 17 August 1944 in New York City, at the age of nine months he contracted pneumonia and his mother gave him to her aunt and uncle for adoption. Ellison moved to Chicago with his adoptive parents where he attended school. Ellison has stated that he did not enjoy school and did not excel academically. He only discovered he was adopted when he was 12 and did not see his biological mother again until he was 48.

Ellison dropped out of college and had a few jobs before starting his first software company SDL in 1977 with two business partners. The company went on to be renamed Oracle and the company made giant databases for notable global companies including IBM, American Airlines and Ford. With a 39% stake in the company, Ellison soon became a billionaire. Read more about Larry Ellison's astonishing life

Amancio Ortega has a mammoth net worth of $70 billion (£55bn) and is the sixth richest person in the world. How did he do it? He co-founded Inditex, best known for its Zara fashion chain, which he started in 1975. But Ortega came from very humble beginnings.

Ortega was born in 1936, just before the outbreak of Spain’s Civil War, and grew up in Leon where his father was a railway worker. Artega left school at 14, moved to A Coruña, and started working as a shop hand at a local shirtmaker. This is where he learnt to make clothes by hand.

Once Ortega had gained enough experience, he and his wife launched a textile manufacturing company then, later on, the Zara brand. Zara soon became very successful due to its quick turnaround of stock and stores opened all around the globe. As for Ortega, he is notoriously private, rarely gives interviews and, unlike fellow billionaires, is known for maintaining a simple lifestyle. Now discover the college droputs who became billionaires