Participants learn how to survive in the wild, including tips on how to make it through a zombie invastion at a “Zombie First Responder” course March 11, 2012 in Sandy, Oregon. In an intensive 2-day curriculum participants train in everything from wilderness and urban survival, nerf or nerd weaponry, stealth and evasion, and proper zombie “disposal”. (Photo by Natalie Behring/Getty Images)

Competitors take part in the Christmas Really Wild Mud Run on a 4.6 miles course across undulating farm land at Celtic Camping, St David's, Pembrokeshire, Wales, December 12, 2015. (Photo by Rebecca Naden/Reuters)

Mud Madness at the annual Jaffa Cakes charity three-mile run at Foymore Lodge near Portadown this afternoon, on April 13, 2014. A total of a thousand competitors and fun-runners took part in the two races held over the mudstrewn endurance course. (Photo by Alan Lewis/Photopress Belfast)

More than 400 people stripped off and ran into freezing waters to celebrate the autumn equinox – and raise money for charity at Druridge Bay, Britain, September 25, 2016. It was the largest turnout the North East Skinny Dip has ever seen in its five-year history, and it was also the first time it has ever rained on the morning of the event. Revellers gathered from 5.30am on Sunday at Druridge Bay, in Northumberland, before baring all in the North Sea. (Photo by David Charlton Photography)

People watch as workers inflate a near-10 metre high giant spider by Singaporean artist Jackson Tan in Singapore's Marina Bay financial district on February 6, 2017. The spider is one of several inflatable creatures that will form the Art-Zoo, a section created by Singaporean artist Jackson Tan for the iLight Marina Bay annual light-art festival in the city-state. (Photo by Roslan Rahman/AFP Photo)

A seal playfully tries to bite the camera, taken on February 2016 in Plettenberg Bay, South Africa. A group of friendly seals get up close and personal with the camera. The pod of brown fur seals, also known as “cape fur seals”, were shot in Plettenberg Bay in South Africa by dive tour operator Rainer Schimpf. The playful creatures prove they are not camera shy in the slightest as they they swim upside down, grin widely and attempt to bite the camera lens. (Photo by Rainer Schimpf/Barcroft Media)

A navy diver storms into the gallery during a military display at Singapore's 52nd National Day celebrations at Marina Bay in Singapore August 9, 2017. (Photo by Edgar Su/Reuters)

A man takes photos of a high tide seen in the Bay Of Bengal before Cyclone Yaas arrives in Digha, 205km South of Kolkata, Eastern India, 25 May 2021. (Photo by Piyal Adhikary/EPA/EFE)