A swimmer disguised as Superman dives into the lake during the 78th “Coupe de Noel” (Christmas cup) swimming race in the Lake Geneva, on December 18, 2016 in Geneva. More than 1800 participants took part in the event, a 12-meter-long swimming off the Geneva's bank in the 7 degrees Celsius cold water. (Photo by Fabrice Coffrini/AFP Photo)

An athlete dressed as a clown jumps into the Mediterranean sea as he takes part in the Copa Nadal in the Spanish port of Barcelona in Barcelona, Spain, Sunday, December 25, 2016. The Copa Nadal (Christmas Cup) is a traditional swimming competition that takes place in Barcelona every December 25th, where participants swim 200 meters in the open sea in the port of Barcelona. (Photo by Manu Fernandez/AP Photo)

Participants of the 77th edition of the annual Christmas swimming 'Coupe de Noel' jump into the waters of Lake Geneva, in Geneva, Switzerland, 20 December 2015. More than 1,540 men and women braved the water temperature of just 8 degrees Celsius as they swam a 120 meters distance at the traditional Christmas swimming in Geneva. (Photo by Salvatore Di Nolfi/EPA)

Looking for a reason to visit the Philippines? This mermaid school should do the trick. No, seriously, there’s an actual school that will teach you how to be a mermaid. It’s called the Philippines Mermaid Swimming Academy. (Photo by Philippine Mermaid Swimming Academy/Exclusivepix Media)

Seals dressed in military uniforms swim during a show marking the 70th anniversary of the end of World War Two, at an aquatic park in the Siberian city of Irkutsk, Russia, May 9, 2015. (Photo by Evgeny Kozyrev/Reuters)

Michal Navratil of the Czech Republic performs after the men's 27 meter high dive final at the Swimming World Championships in Kazan, Russia, Wednesday, August 5, 2015. (Photo by Denis Tyrin/AP Photo)

Skiers and snow boarders descend from a slope as they attempt to break the record for mass skiing in swimming suits at Rosa Khutor resort near Sochi, Russia, April 9, 2016. (Photo by Kazbek Basayev/Reuters)

Gold medallists of China perform Synchronised Swimming Free Combination routine at the Munhak Park Tae-hwan Aquatics Center during the 17th Asian Games in Incheon September 23, 2014. (Photo by Tim Wimborne/Reuters)