Patrick Hausding and Stephan Feck of Germany compete in the men's 3-meter synchro springboard preliminary competition at the FINA Swimming World Championships in Barcelona, Spain, Tuesday, July 23, 2013. (Photo by David J. Phillip/AP Photo)

Visitors watch as Grigory Broverman, a member of the Cryophile winter swimmers club, pours a bucket of cold water over his 6-year-old daughter Liza during a flash mob, part of a celebration of Polar Bear Day at the Royev Ruchey Zoo in a suburb of the Siberian city of Krasnoyarsk, Russia, November 29, 2015. The air temperature was around minus 5 degrees Celsius. (Photo by Ilya Naymushin/Reuters)

A swimmer competes during the UK Cold Water Swimming Championships at Tooting Bec Lido in south London January 24, 2015. (Photo by Luke MacGregor/Reuters)

A competitor dressed up as Santa Claus jumps into the sea during the 102nd Barcelona Traditional Christmas Swimming Cup at the Old Harbour of Barcelona on December 25, 2011 in Barcelona, Spain. (Photo by David Ramos/Getty Images)

Swimmers in fancy dress splash as they participate in the New Year's Day Loony Dook swim at South Queensferry, Scotland January 1, 2015. (Photo by Russell Cheyne/Reuters)

Ice swimmer Klaudia prepares to swim in a filled up water kettle in an ice cave inside the Nature Ice Palace, with a hight of 3,250 meters (10,663 feet) above sea level, at Hintertux Glacier near Hintertux, some 480 kilometers (298 miles) western of Vienna, Austria, 28 July 2018. (Photo by Christian Bruna/EPA/EFE)

Chincoteague Ponies swim across Assateague Channel in a heavy downpour on Wednesday, July 24, 2013 during the 88th Annual Chincoteague Pony Swim. A portion of the herd will be auctioned on Thursday. (Photo by Jay Diem/Eastern Shore News)

A child attends a training session in a swimming pool on July 10, 2007 in Wuhan of Hubei Province, China. (Photo by China Photos/Getty Images)