Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870

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

American model and television personality Kendall Jenner attends the Tiffany & Co. Paper Flowers event and Believe In Dreams campaign launch on May 3, 2018 in New York City. (Photo by Jamie McCarthy/Getty Images for Tiffany & Co.)

Figure Skating, ISU Grand Prix Rostelecom Cup 2016/2017, Ice Dance Short Dance, Moscow, Russia on November 4, 2016. Kaitlyn Weaver and Andrew Poje of Canada compete. (Photo by Grigory Dukor/Reuters)

Tarah Kayne and Daniel O'Shea of the U.S. perform during the Pairs short program at the Skate America figure skating competition in Milwaukee, Wisconsin October 23, 2015. Fifty-six Olympic and world championship athletes are competing in the event, which is the first of six stops on the International Skating Union (ISU) Grand Prix of Figure Skating Series. (Photo by Lucy Nicholson/Reuters)

Children play on an abandoned car near a protest, which is against the dissolution of Yemen's parliament and the Shi'ite Muslim Houthi militia's tightening grip on power, in the southwestern city of Taiz, February 13, 2015. (Photo by Mohamed al-Sayaghi/Reuters)

Takeoka Chisaka, Hiroshima, Japan. “One morning in August 1945, I was walking home from the night shift at a factory in Hiroshima. As I reached my door, there was a huge explosion. When I came to, my head was bleeding and I had been blasted 30m away. The atomic bomb had detonated. When I found my mother, her eyes were badly burned. A doctor said they had to come out, but he didn’t have the proper tools so used a knife instead. It was hellish. I became a peace-worker after the war. In the 1960s, at a meeting at the UN, I met one of the people who created the atomic bomb. He apologised”. (Photo and caption by Sasha Maslov)

A woman reacts as she uses a selfie stick to take a photo of herself at Tiananmen Square in Beijing, China, Thursday, April 30, 2015. Selfie sticks are gaining popular in China, and many people are using them at popular tourist destinations. (Photo by Andy Wong/AP Photo)