Men slide in the mud during the Boryeong Mud Festival at Daecheon Beach in Boryeong, South Korea, Saturday, July 22, 2017. The 20th annual mud festival features mud wrestling and mud sliding. (Photo by Ahn Young-joon/AP Photo)

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)

One of the two one-year-old albino alligator is seen in a vivarium at the Tropical aquarium in Paris. The two alligators are the result of a captive breeding program which protect endangered species and will presented to the public in a vivarium. (Photo by Philippe Wojazer/Reuters)

A spinning top is seen on a hand during a performance at Sanxia old street in New Taipei City, Taiwan May 8, 2016. Taiwan's ancient folk art of spinning tops is kept alive by a group of enthusiasts who perform intricate tricks with the toys at a temple in Taipei, the capital. (Photo by Tyrone Siu/Reuters)

A diver dressed in a Santa Claus costume performs with sardines at the Coex Aquarium in Seoul, South Korea, Wednesday, December 9, 2015. (Photo by Ahn Young-joon/AP Photo)

Honorable Mention: “The Storm”. During I was taking photo with my nephew, the storm came and I caught this beautiful moment. Photo location: Kocaeli, Turkey. (Photo and caption by Aytül Akbaş/National Geographic Photo Contest)

People pause at a memorial set up for victims of a mass shooting in Las Vegas, Nev., on Tuesday, October 3, 2017. A gunman opened fire on an outdoor music concert on Sunday. It was the deadliest mass shooting in modern U.S. history, with dozens of people killed and hundreds injured, some by gunfire, some during the chaotic escape. (Photo by John Locher/AP Photo)

A stag deer stands in the road in Richmond Park, in west London, Britain, December 27, 2017. (Photo by Hannah McKay/Reuters)