Hundreds of hardy swimmers across Britain braved jumping into freezing cold waters for a annual Christmas Day dip on December 25, 2017. (Photo by Dave Nelson/The Sun)

Swimmers prepare to take part in the annual Christmas Day Peter Pan Cup handicap race in the Serpentine River, in Hyde Park, London, December 25, 2015. (Photo by Andrew Winning/Reuters)

Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

A newly born Indian white tiger cub yawns in its enclosure at Liberec Zoo, Czech Republic, April 25, 2016. (Photo by David W. Cerny/Reuters)

A protester reacts as police use water cannon during a demonstration to demand changes in the Chilean education system in Santiago, Chile June 25, 2015. (Photo by Ueslei Marcelino/Reuters)

An aerial view of the Grand Mosque is seen on the second day of Eid al-Adha, during the annual haj pilgrimage in the holy city of Mecca September 25, 2015. (Photo by Ahmad Masood/Reuters)

A giant river otter, the world's largest otter species, looks out of its enclosure at the newly completed River Safari in Singapore, on March 25, 2013. (Photo by Wong Maye-E/Associated Press)

A woman jumps out of a street art object in the center of the Ukrainian capital of Kiev during a warm autumn day on September 25, 2020. (Photo by Sergei Supinsky/AFP Photo)