These 10 people didn't have greatness thrust upon them. They weren't born great. They faced challenges and prejudices and misconceptions. And despite it all, they chose to stretch the limits of what they could do, and in the process, they became truly exceptional.

Amelia Earhart

Born in Kansas on July 24, 1897, aviation pioneer Amelia Earhart became the first woman to receive the U.S. Distinguished Flying Cross from Congress. The award was granted after she flew her Lockheed Vega from Newfoundland in Canada to Culmore in Northern Ireland in 1932 -- the first woman to fly solo across the Atlantic.

Earhart vanished over the Pacific in 1937 in a record attempt to fly around the world at the equator. Her final resting place remains a mystery. Meanwhile, researchers are scouring over data gathered during a deep-water search for her plane in the Pacific.

Daniel Dias appears with Brazilian President Dilma Rousseff.Dilma Rousseff/Wikimedia Commons

Swimmer Daniel Dias was inspired by another Brazilian athlete, Clodoaldo Silva, who set four world records in swimming at the 2004 Paralympics. Two years later Dias made his own splash, winning five medals in his first international competition. In the London games, he took six gold -- all in record time.

Dias, born with malformed upper and lower limbs, also won more gold medals at the 2008 Summer Paralympics in Beijing. He's considered a favorite at home in the 2016 Paralympic Games, to be held in Rio de Janeiro.

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Born prematurely, Wilma Rudolph weighed a mere four and a half pounds. At age 4, Rudolph contracted polio, forcing her to wear leg braces for five years and orthopedic shoes for two years after that.

Five years after she started running at all, Rudolph made her first performance at the Olympics. Then in 1960, Rudolph showed the world what she could do. At the Summer Olympics in Rome, Rudolph claimed three gold medals in the 100-meter, the 200-meter and the 4x100-meter relay race. She also managed to set two world records.

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The 1936 Olympic Games in Berlin were designed to deliver a propaganda coup for the Nazi Party and Adolf Hitler. The games would highlight the alleged superiority of the Aryan race in physical competition. Apparently, the Nazis didn't count an African-American athlete spoiling their plans.

Jesse Owens dominated the games, taking home an astounding four gold medals in track and field events including the long jump, the 100-meter, the 200-meter and the 4x100-meter relay race.

kepler.nasa.gov

Before being recruited as a cosmonaut, Russian Valentina Tereshkova was a textile-factory assembly worker and an amateur parachutist. She was selected out of more than 400 applicants to pilot the Vostok 6, and on June 16, 1963, she became the first woman and the first civilian in space.

When the first group of female cosmonauts was disbanded in 1969, she became a prominent member of the Communist Party of the Soviet Union, holding various political offices. After the collapse of the Soviet Union, she stayed in politics. She's still revered as a hero in post-Soviet Russia.

Red Bull Stratos

High above New Mexico on Oct. 14, 2012, a helium-filled balloon ascended to around 128,000 feet carrying Felix Baumgartner into the history books. The Austrian daredevil leaned forward and slowly stepped into the void. Then gravity took over, causing him to plummet through the stratosphere. He traveled faster than the speed of sound.

"I know the whole world is watching now, and I wish the world could see what I see," Baumgartner said just before he jumped. "And sometimes you have to go up really high to see how small you really are."

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Explorer Ann Bancroft's resume reads like the work of several adventurers. In 1986, Bancroft became the first woman to reach the North Pole on foot and by dogsled. She was also the first woman to cross both polar ice caps to reach the North and South Poles, as well as the first woman to ski across Greenland.

In 1993 Bancroft led a four-woman expedition to the South Pole on skis. In 2001, she and her friend Liv Arnesen became the first women to ski across Antarctica.

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"The Guinness Book of World Records" calls British adventurer Ranulph Fiennes the world's greatest living explorer. Fiennes was the first person to reach both poles, the first to cross the Antarctic and Arctic Oceans and the first to circumnavigate the globe along its polar axis.

Fiennes once ran seven marathons in seven days on seven continents. And at at age 65 -- he's now nearly 70 -- Fiennes climbed to the summit of Mount Everest. This year he attempted to be the first person to cross the South Pole on skis during the brutal Antarctic winter. But he had to be evacuated after suffering from frostbite.

Kilian Jornet Burgada (right), climbs the Grand Mont pass at 2,687 meters during the 23rd Pierra-menta ski-climbing race.AFP/Getty Images

Kilian Jornet Burgada is a ski mountaineer who has dominated endurance competitions, including the Duathlon which combines mountain running and mountain biking.

The New York Times called Burgada "the most dominating endurance athlete of his generation. In just eight years, Jornet has won more than 80 races, claimed some 16 titles and set at least a dozen speed records, many of them in distances that would require the rest of us to purchase an airplane ticket." He sometimes runs an entire day consuming only wild berries and water from streams.

Stephen Hawking floats aboard a Zero Gravity Corp. parabolic flight in Florida in 2007. Zero Gravity Corp

Now 71, renowned astrophysicist Stephen Hawking was once told he wouldn't live past his 20s. In his many unexpected years, Hawking has contributed to our knowledge of gravity and other concepts in the universe.

Despite spending most of his life crippled in a wheelchair and able to speak only through a computer, the theoretical physicist's quest for the secrets of the universe has made him arguably the most famous scientist in the world.

"I'm sure my disability has a bearing on why I'm well known," Hawking once said. "People are fascinated by the contrast between my very limited physical powers, and the vast nature of the universe I deal with."