6 of the youngest ever athletes to compete at the Olympics - and 5 of the oldest

At 13 years old, Donna de Varona was the youngest member of the US swimming team at the 1960 Olympics.

de Varona won two gold medals at the following Olympics in Tokyo in 1964. By the time she retired from swimming at age 17, she had broken 18 world records.

At the 1936 Olympics in Berlin, 13-year-old Marjorie Gestring won a gold medal in springboard diving.

Gestring still holds the world record for the youngest individual Olympic gold medalist.

Klaus Zerta, age 13, won a gold medal as a coxswain at the 1960 Olympics along alongside rowers Bernhard Knubel and Heinz Renneberg.

Zerta was the youngest medalist at the 1960 Olympics in Rome, and the youngest gold medalist in Germany's history.

13-year-old Gaurika Singh of Nepal was the youngest athlete at the 2016 Olympics in Rio.

Singh holds the Nepalese record for the 100-meter backstroke. She placed 31st in the event at the 2016 Olympics.

In 1996, Dominique Moceanu became the youngest US gymnast to win gold when she was 14.

Moceanu was a member of the "Magnificent Seven," the first US gymnastics team to win the team gold medal.

Tara Lipinsky remains the youngest ever gold medalist in Olympic figure skating since her win at the 1998 Olympics at 15 years old.

Lipinski became the first woman to land a triple loop-triple loop in competition, beating Michelle Kwan to win the gold medal. Lipinski went on to become a professional figure skater with Stars on Ice and commentator with fellow skater Johnny Weir.

Dara Torres became the oldest swimmer to win an Olympic medal at the 2008 Olympics at age 41.

Out of the five Olympic Games Torres competed at, she was the oldest US swimmer at two of them. She won a total of 12 Olympic medals over her swimming career — four each of gold, silver, and bronze.

Gymnast Oksana Chusovitina, age 46, is set to compete in her eighth Olympic Games this summer in Tokyo.

Chusovitina is the oldest gymnast in Olympic history. She won a team gold medal with the Soviet Union in 1992, and a silver medal while representing Germany in 2008. She will represent Uzbekistan in Tokyo.

At 66 years old, equestrian Mary Hanna will become the second-oldest female Olympian in history this summer.

Hanna will represent Australia in Tokyo this summer — her sixth Olympic Games since 1996.

Lorna Johnstone of Great Britain remains the oldest woman to ever compete in the Olympics at 70 years old.

Johnstone competed in equestrianism at the 1968 and 1972 Olympics. After her Olympic run, she was inducted into the Royal Horse Society Hall of Fame.

Equestrian Hiroshi Hoketsu competed in the 2012 London Olympics at age 71.

Hoketsu's first Olympic Games were in Tokyo in 1964. He also competed in Beijing in 2008. He is the third-oldest Olympian in history after 72-year-old equestrian Arthur von Pongracz of Austria and 72-year-old shooter Oscar Swahn of Sweden.