Adult film actress/director Joanna Angel and her husband, adult film actor Small Hands, attend the 2018 Adult Video News Awards at the Hard Rock Hotel & Casino on January 27, 2018 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

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)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

Irina, worker of a petrol station, now member of reconnaissance team of pro-Russian rebels' in the town of Makievka, eastern Ukraine, October 6, 2014. Like the men in the conflict, the women come from all walks of life. Some women come to serve with their husbands and boyfriends, others are single. Female fighters on both sides said the men in their units treat them as equals, though sometimes showing more leniency. They have little respect for men who have not taken up arms. On both sides the fighters expect a long conflict, despite the fragile ceasefire now in place. (Photo by Shamil Zhumatov/Reuters)

Visitors look at an artwork “Hierarchy of Prosperity” created by Indonesian artist Eko Nugroho during the VIP preview of the art fair “Art Basel” in Hong Kong, Tuesday, March 22, 2016. A set of gold-plated metal cubes, tapestries embroidered by unknown North Korean artisans and bales of cardboard waste are among the highlights of the Art Basel Hong Kong fair opening this week. (Photo by Kin Cheung/AP Photo)

A visitor looks at portraits of Mao Zedong amid his statues on display at a wholesale souvenir store in Shaoshan, Hunan Province in central China, 28 April 2016. Shaoshan is the hometown of former Communist leader Mao Zedong, popularly known as Chairman Mao. Thousands of visitors descend on this small Chinese town burrowed in the hills of Central China's Hunan province to pay homage to the “Great Helmsman” everyday. It is one of the core sites of the “Red Tourism” industry, where communist party cadres and ordinary Chinese tourists alike seek to relive the experiences and rekindle the spirit of the revolutionaries. (Photo by How Hwee Young/EPA)

A member of the Revolutionary Armed Forces of Colombia (FARC) pose for a picture at a camp in the Colombian mountains on February 2005. (Photo by Frank Piasecki Poulsen)

Catholic pilgrim Matilde Madalena de Jesus crawls on a rocky trail carrying a bottle of water on her head during the annual pilgrimage of the dead (Romaria dos Finados), in the city of Juazeiro do Norte, Ceara state, in Brazil October 31, 2016. (Photo by Ueslei Marcelino/Reuters)