A US Army M1A2 SEP tank participates in the Strong Europe Tank Challenge 2017 at the military training area in Grafenwoehr, Germany, 12 May 2017. Six North Atlantic Treaty Organization (NATO) nations and partner nations, Austria, France, Germany, Poland, Ukraine and the USA are taking part in this competing exercise. (Photo by Christian Bruna/EPA)

US actress Alexandra Daddario attends the “Baywatch” Photo Call in Berlin on May 30, 2017 in Berlin, Germany. (Photo by Splash News and Pictures)

Japanese chorus girls appear to be drilling in military tactics atop their theater building as they perform salutes, June 30, 1937. The officer is from the Japanese regular army and says the girls display more rhythm in their drills than do the regular troops. (Photo by AP Photo)

This family of warthogs regularly visited our campsite in the Ethiopian highlands so I set up a remote camera with a wide-angle lens to photograph them as they rummaged around for food. They just had a mud bath. (Photo by Will Burrard-Lucas/Caters News Agency)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)

In this November 2, 2018 photo, a voodoo believer who is supposed to be possessed with Gede spirit performs rituals near Baron Samedi's tomb during the annual Voodoo festival Fete Gede at Cite Soleil Cemetery in Port-au-Prince, Haiti. As a proof that they got into trance and their bodies got possessed by Gedes, they drink and wash their faces, their eyes and even their genitals with a mixture of raw rum and hot chili peppers that, according to believers, could burn the skin of any human alive. (Photo by Dieu Nalio Chery/AP Photo)

A participant, surrounded by red chilli peppers, takes part in a chilli-eating competition at a hot spring in Yichun, Jiangxi province, China on December 9, 2018. (Photo by Chen Fei/China News Service via Reuters)

Christmas party goers seen on December 14, 2018 in Liverpool, United Kingdom. Revellers hit the bars as they partied hard on the second-to-last Friday before Christmas. (Photo by Mercury Press)