- Representing USA
Swimming sensation Ledecky won five Olympic Games gold medals and was a nine-time world champion, all while still a teenager.
Aged 19, she was the most decorated female athlete at Rio 2016, winning the 200m, 400m and 800m Freestyle titles, and taking a gold and silver as part of the United States' 4x200m and 4x100m Freestyle Relay teams.
She began swimming aged six - nine years later she was an Olympic champion for the first time, winning the 800m Freestyle at London 2012.
In an incredible race, Ledecky headed into the 750m turn under world record pace and while she failed to break it, she announced her arrival by finishing four seconds clear of the field.
She did better Rebecca Adlington's world record at the 2013 World Championship, and also set the best-ever time in the 1500m Freestyle, two of four gold medals she won at the event.
At the 2015 World Championships, she retained her 400m, 800m, 1500m and 4x200m titles - with two more world records - and added the 200m Freestyle crown.
Her dominance of the sport was further underlined at Rio 2016, with golds in the 200m, 400m and 800m Freestyle, breaking the world records in the latter two races once more.
Ledecky's exploits saw her become the first swimmer to win the 200m, 400m and 800m Freestyle events at the same Olympics since the Games in Mexico City in 1968.
Following her performance in Rio, Ledecky was pictured alongside Olympic swimming legend Michael Phelps and gymnast Simone Biles in an issue of Sports Illustrated which billed them as “The Greatests.”
The niece of New York Islanders Ice Hockey team owner Jon Ledecky, she was named FINA Swimmer of the Year in 2014 and in 2016 was the youngest person on the TIME Magazine's list of the 100 most influential people.