A staff member sets up a ROBOTLEO robot at the Global Mobile Internet Conference (GMIC) 2017 in Beijing, China April 28, 2017. (Photo by Jason Lee/Reuters)

A worker roasts rows of freshly slaughtered pigs, known locally as “lechon” and famously served as main courses during the New Year revelry, at a store in Manila, Philippines, December 31, 2016. (Photo by Ezra Acayan/Reuters)

Indigenous women from the Kamayura tribe take part in a demonstration of Huka Huka fight at the first World Games for Indigenous Peoples in Palmas, Brazil, October 29, 2015. (Photo by Ueslei Marcelino/Reuters)

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)

Two dogs sent into outer space by the Soviet Union after their safe return to earth. They spent 22 days in orbit. (Photo by Central Press/Getty Images). 22nd March 1966

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

Two traditional folk dancers performing in Teheran, Iran. (Photo by Keystone Features/Getty Images). 25th January 1961