St Andrews University students skinny dip in the sea as May Day celebrations in St Andrews, Scotland on April 30, 2017. Hundreds of revellers ditched their clothes and bravely jumped into the bitterly cold North Sea. (Photo by Alamy Stock Photos)

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)

Tuvalu Beneath the Rising Tide by Sean Gallagher, Tuvalu. Changing environments prize: Fallen trees lie on a beach as the waves from the Funafuti lagoon in Tuvalu lap around them. Land erosion has always been a problem for the South Pacific country but problems are intensifying as sea levels rise. Rising seas are on the verge of completely submerging the tiny archipelago’s islands. (Photo by Sean Gallagher/CIWEM Environmental Photographer of the Year 2019)

A migrant woman pulls a girl out of the water as refugees and migrants arrive on an overcrowded dinghy in rough sea on the Greek island of Lesbos, after crossing a part of the Aegean Sea from the Turkish coast, October 2, 2015. A record number of at least 430,000 refugees and migrants have taken rickety boats across the Mediterranean to Europe this year, 309,000 via Greece, according to International Organization for Migration figures. (Photo by Dimitris Michalakis/Reuters)

A devotee of the Afro-Brazilian goddess of the sea Lemanja pays tribute on Lemanja's Day at Ramirez beach in Montevideo February 2, 2015. On this day every year, worshippers light candles at a shrine and throw sweets, alcoholic drinks, fruits and cheap jewellery into the sea as offerings to ask for good health and luck in love and work. (Photo by Andres Stapff/Reuters)

A tourist takes photos of an Aurora Borealis display (Northern Lights) over the Bals-Fiord north of the Arctic Circle, near the village of Mestervik late September 30, 2014. (Photo by Yannis Behrakis/Reuters)

Visitors crowd an artificial wave swimming pool at a tourist resort to escape the summer heat in Daying county of Suining, Sichuan province, China, July 11, 2015. (Photo by Reuters/Stringer)

Tourists watch the sunrise and pray outside a church on the summit of Mount Moses, near the city of Saint Catherine, in the Sinai Peninsula, south of Egypt, December 9, 2015. (Photo by Amr Abdallah Dalsh/Reuters)