A rescue helicopter is shown at the Mount Everest south base camp in Nepal a day after a huge earthquake-caused avalanche killed at least 17 people, in this photo courtesy of 6summitschallenge.com taken on April 26, 2015 and released on April 27, 2015. Rescue teams, helped by clear weather, used helicopters to airlift scores of people stranded at higher altitudes, two at a time. (Photo by Reuters/6summitschallenge.com)

Two life-size Victorian style dolls shocked Londoners morning December 3, 2015 as the creepy pair popped up at commuter hotspots across the capital to mark the launch of the world's first psychological theme park ride created by Derren Brown, coming to Thorpe Park Resort in 2016. (Photo by Matt Alexander/PA Wire)

“Sidney D. Gamble (July 12, 1890 – 1968) was born in Cincinnati, Ohio, to David Berry and Mary Huggins Gamble; grandson of James Gamble, who, with William Procter, founded Procter & Gamble in 1837. in 1912 he graduated magna cum laude from Princeton University with a Bachelor of Literature degree and was elected to Phi Beta Kappa. He visited China for four extended periods, 1908, 1917–1919, 1924–27, and 1931–1932, doing Christian social work for the Y.M.C.A and conducting social surveys. He is now best known for his remarkable and extensive photographs of Peking and North China.” – Wikipedia. (Photo by Sidney David Gamble via Duke University Libraries)

Photo: Hillcoat Riding Fu Tu. China, An Xian, 1917-1919. P.S. All photos are available in high resolution.

A Naga sadhu, or naked Hindu holy man, performs a ritual inside his tent during Kumbh Mela, or Pitcher festival, at Trimbakeshwar, India, Friday, August 28, 2015. Hindus believe taking a dip in the waters of a holy river during the festival will cleanse them of their sins. The festival is held four times every 12 years. (Photo by Rajanish Kakade/AP Photo)

Lilly Caron, 8, of Bridgeton, Maine, Jason Homchick, of San Diego, and Lilly's father Jason Caron, (obscured), ride the Sky Swing at Seacoast Adventure, Thursday, July 14, 2016, in Wyndham, Maine. The 100-foot-tall swing gives riders the combined thrills of sky diving and hang gliding. (Photo by Robert F. Bukaty/AP Photo)

Two models sit in an acrylic “ZF-Car” from the German manufacturer of the same name at the Automechanika automotive service industry trade fair in Frankfurt am Main, Germany, 12 September 2016. The Automechanika Fair runs from 13 to 17 September 2016. (Photo by Boris Rössler/EPA)

Contorsionist Rich Miteku performs during the opening of the 41st Monte-Carlo International Circus Festival in Monaco on January 19, 2017. (Photo by Valery Hache/AFP Photo)

A vervet monkey passes in front of a woman on the shores of lake Naivasha, Kenya January 24, 2017. (Photo by Goran Tomasevic/Reuters)