The son of sharecroppers, Jackie Robinson overcame poverty and racism to become a sports legend, breaking the color barrier in Major League Baseball when the Brooklyn Dodgers hired him in 1947 to play second base. The first black man to play in the major leagues since 1889, Robinson was instrumental in ending racial segregation in professional baseball, and his example contributed to the success of the Civil Rights Movement. During his 10 seasons in professional baseball, Robinson played in six World Series and was chosen for six consecutive All-Star Games. He received the first-ever Major League Baseball Rookie of the Year Award in 1947 and the National League MVP Award in 1949. In 1962, he was inducted into the Baseball Hall of Fame.

Oscar Pistorius is a South African sprinter knows as the "Blade Runner" and "the fastest man on no legs." Although both of his legs were amputated below the knee when he was less than a year old, Pistorius participated in sports such as rugby, tennis, water polo and wrestling during his school years. He started running with special prosthetics in January 2004 during rehabilitation for a serious rugby knee injury. He now holds word records in the 100-, 200- and 400-meter events (sport class T/44) for athletes with a range of leg disabilities, and in 2011 he became the first amputee to win a medal in a world track event for able-bodied athletes.

Wilma Rudolph caught infantile paralysis (polio) as a young child, which twisted her left leg and foot and made it necessary for her to wear a brace for three years. Despite those early challenges, Rudolph grew up to become a runner who was considered the world's fastest woman during her competitive years. Rudolph competed in two Olympic Games (1956 and 1960). In the 1960 Summer Olympics in Rome, Rudolph became the first American woman to win three gold medals in track and field during a single Olympic Games.

Bethany Hamilton started surfing professionally as a young girl, but at age 13 she lost her left arm and nearly lost her life when she was attacked by a shark while surfing in her home waters off Kauai. Less than a month later, she was back on her board and surfing again. Two years later, in 2005, Hamilton won first place in the National Scholastic Surfing Association (NSSA) National Championships, a goal she had been working toward before the shark attack. In 2008, she started competing full-time on the Association of Surfing Professionals World Qualifying Series. In her first competition against many of the world's best female surfers, she finished second.

Babe Didrikson Zaharias was an outstanding all-around athlete who challenged traditional perceptions of femininity at a time when most women were expected to stay at home and take care of their husbands and children. Zaharias won two gold medals and one silver in track and field at the 1932 Olympics, and became a champion golfer after coming late to the game. When she represented her employer in the 1932 Amateur Athletic Union Championships, she competed in eight out of ten events, won five, tied for first place in a sixth, and set five world records in a single afternoon. She was also an expert seamstress who made many of her own clothes, including the outfits she wore as a professional golfer. The Associated Press placed Zaharias at #9 on its list of the Greatest Athletes of the 20th Century.

The colt was too small and had knobby knees, and the only things that seemed to interest him were eating and sleeping. He was nobody's idea of a champion racehorse, but that is exactly what Seabiscuit became, and during the Great Depression he was a symbol of hope to millions of people -- the underdog who only needed a second chance to make a comeback and succeed. After an inauspicious beginning -- he lost his first 17 races -- Seabiscuit went on to become the greatest racehorse in America during the 1930s. In his most famous race, Seabiscuit defeated the Triple Crown champion War Admiral in a match race at Maryland's Pimlico Race Course, winning by four lengths.

Melissa Stockwell, a former U.S. Army officer, lost her left leg when a roadside bomb exploded as she was leading a convoy in Iraq. Stockwell, who received the Bronze Star and the Purple Heart for her service in Iraq, started swimming as part of her physical therapy at Walter Reed Hospital in Washington, D.C. She competed for the U.S. team in the 2008 Paralympic Games, where she set world records for the 100-meter butterfly and the 100-meter freestyle events. Stockwell is also the reigning two-time Paratriathlon World Champion in her class.

Few things are as inspiring as perfection. At age 14, at the 1976 Olympics in Montreal, Romanian gymnast Nadia Comăneci scored the first perfect 10 ever awarded a gymnast in the history of the modern Olympic Games. The achievement was so unexpected that the scoreboards were not even equipped to display a score of 10.0. Comăneci scored six more perfect 10s in Montreal, on her way to winning three gold medals, one silver and one bronze. Four years later, she won two more golds and two silvers at the 1980 Olympic Games in Moscow.

Fourteen years after her death, Florence Griffith-Joyner, or Flo-Jo as her fans and the media called her, is still considered "the fastest woman of all time" because she still holds the world records for both the 100-meter and 200-meter events that she set in 1988. She grew up poor in a public housing project in Los Angeles, but went on to win a silver medal at the 1984 Olympics in Los Angeles and three gold medals and a silver at the 1988 Olympics in Seoul, South Korea. Later in her short life she struggled with a congenital condition that made her prone to seizures. She died at 38 when she suffocated in her sleep during a seizure.

Jim Thorpe, who was of mixed European and Native American heritage, faced racism and prejudice all his life. But Thorpe was an unusually gifted athlete, who played professional football, basketball and baseball and won Olympic gold medals for both the decathlon and pentathlon in 1912. He was stripped of his medals after it was discovered that he had played two seasons of semi-pro baseball before competing in the Olympics and could not be considered an amateur athlete, but the medals were reinstated 30 years after his death. In a poll of sports fans conducted by ABC Sports, Thorpe was voted the Greatest Athlete of the Twentieth Century, edging out 14 other great athletes, including Muhammad Ali, Babe Ruth, Jesse Owens, Jack Nicklaus and Michael Jordan.