A instructor (2nd L) from the Philippine Mermaid Swimming Academy assists participants of a monofin swimming summer workshop as they practise floating in the water of a private pool in Paranaque city, metro Manila April 5, 2014. The Philippine Mermaid Swimming Academy workshops, which were originally conducted on the beaches of Boracay Island, central Philippines, currently cost 1,800 pesos per person ($40) for a two-hour session. (Photo by Romeo Ranoco/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)

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)

Models pose backstage ahead of the Gary Bigeni show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 4, 2011 in Sydney, Australia. (Photo by Matt King/Getty Images)

A model showcases designs by Antonia Paris during the Women's RTW 3 catwalk during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 5, 2011 in Sydney, Australia. (Photo by Stefan Gosatti/Getty Images)

Models present creation for the 7th Hosa Cup China Swimwear Design contest and Hosa Swimwear Trend fashion show on day five of China Fashion Week A/W 2011 on March 28, 2011 in Beijing, China (Photo by Feng Li/Getty Images)

A model prepares backstage at the Meskita fashion show during Mercedes-Benz Fashion Week Spring 2015 on September 4, 2014 in New York City. (Photo by Larry Busacca/Getty Images for Meskita)

A model presents a creation from the Tom Ford Spring/Summer 2015 collection during London Fashion Week September 15, 2014. (Photo by Suzanne Plunkett/Reuters)