BEIJING - AUGUST 21: Thomas Lurz of Germany competes in the men's marathon 10km swimming event held at the National Aquatics Center during Day 13 of the Beijing 2008 Olympic Games on August 21, 2008 in Beijing, China.

BEIJING - AUGUST 21: Vladimir Dyatchin (blue cap) of Russia competes in the men's marathon 10km swimming event held at the National Aquatics Center during Day 13 of the Beijing 2008 Olympic Games on August 21, 2008 in Beijing, China.

BEIJING - AUGUST 20: Cassandra Patten of Great Britain competes in the Women's Marathon 10km swimming event at the Shunyi Olympic Rowing-Canoeing Park during Day 12 of the Beijing 2008 Olympic Games on August 20, 2008 in Beijing, China.

Sharon van Rouwendaal of the Netherlands celebrates her victory in the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.

Rachele Bruni of Italy competes in the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.

Sharon van Rouwendaal of the Netherlands competes in the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.

Keri-Anne Payne of Great Britain competes in the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.

Isabelle Haerle of Germany competes in the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.

Haley Anderson of the United States of America competes in the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.

Rachele Bruni of Italy (Silver), Sharon van Rouwendaal of the Netherlands (Gold) and Poliana Okimoto of Brazil (Bronze) pose on the podium during the medal ceremony for the Women's 10km Marathon Swimming on day 10 of the Rio 2016 Olympic Games at Fort Copacabana on August 15, 2016 in Rio de Janeiro, Brazil.