Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)

Young couple in BDSM action on the leather sofa. (Photo by Alamy Stock Photo)

«Mignon 2». A.E.G., Berlin, Germany, 1905. Despite its unusual appearance, the Mignon typewriter is of a very clever design, giving a smooth and fast operation for typing. (Photo and caption by Martin Howard/Martin Howard Collection)

In this April 14, 2014 file photo, Hamamatou Harouna, 10, who lost the use of her legs to polio, crawls to the restroom on the grounds of the Catholic Church where she and hundreds of others found refuge after fleeing violence in her village, in Carnot, Central African Republic. Health authorities on Tuesday, August 25, 2020 are expected to declare the African continent free of the wild poliovirus after decades of effort, though cases of vaccine-derived polio are still sparking outbreaks of the paralyzing disease in more than a dozen countries. (Photo by Jerome Delay/AP Photo/File)

A fisherman with a close bond to cormorants uses the flock of birds to catch big fish in Li river in Guilin, China. The aquatic birds can be seen perching on a bamboo raft before swooping into the calm water to grasp hold of prey. (Photo by Julia Wimmerlin/Solnet News & Photo Agency)

Huang Wensi in action during her final training session in Ningbo, Zhejiang province, China, before she heads to Taiwan for her Asia Female Continental Super Flyweight Championship match, September 23, 2018. Huang is one of a small but growing number of women in China to embrace professional boxing, relishing its intense nature despite traditional stereotypes that steer women away from such activities. “A women is not just limited to being a wife or mother in the house”, she said. (Photo by Yue Wu/Reuters)

Spacewalker Mark Vande Hei took his own photograph during the first spacewalk of 2018, on January 23, 2018. These sky-high pictures are better known as “space-selfies”. (Photo by Mark Vande Hei/NASA)

An octopus is filmed by the National Oceanic and Atmospheric Administration ship Okeanos Explorer and its robotic sub. (Photo by National Oceanic and Atmospheric Administration)