A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

Winner of the Sandow bodybuilding competition, Mr. Murray. (Photo by Reinhold Thiele/Thiele/Getty Images). Circa 1905

A woman poses with her tattoo during the Shanghai Tattoo Extreme & Body Art Expo 2017 in Shanghai, China September 2, 2017. (Photo by Aly Song/Reuters)

Private Harold L. Langhofer edges into the ball-turret, March 9, 1943. Curled in this position, he can turn the turret so that it fires in any direction. The turret can also be swung around so that the hatch opens into the plane, and the gunner can crawl into it while the Flying Fortress is in motion. (Photo by AP Photo)

A mother prays for success for her child in the college entrance examinations at a Buddhist temple in Seoul, South Korea, November 12, 2015. About 630,000 students on Thursday sat for the annual exams that could lead them to one of the country's top universities. In South Korea, there is no higher achievement than to be accepted by a prestigious university. As a result, many students prepare for these entrance exams from an early age, often studying up to 16 hours a day for years to take this test. (Photo by Kim Hong-Ji/Reuters)

British-based Ukrainians gather outside the Russian Embassy in London to protest against the build-up of troops in the Crimea region, on March 2, 2014. The demonstrators chanted and held banners demanding “Hands off Ukraine”. (Photo by John Stillwell/PA Wire)

A man feeds monkeys at Longchi scenic area, in Dujiangyan, Sichuan province, China May 24, 2017. (Photo by Reuters/Stringer)

A woman counts her money as she sells flowers ahead of International Women's Day in central Kiev, Ukraine on March 7, 2019. (Photo by Gleb Garanich/Reuters)