A horse named Quinn, with a skeleton painted on it to help educate officers, is pictured during a visit by Britain's Queen Elizabeth II (unseen) and Britain's Prince Charles, Prince of Wales (unseen) to the Household Cavalry Mounted Regiment at the Hyde Park Barracks in west London on October 24, 2017. (Photo by Chris Jackson/AFP Photo)

Dr. P.A. Smithe was sent by the American Red Cross as a doctor and surgeon to work at a hospital in Vienna. He sailed to Europe in December 1915 and returned home in August 1916, according to his daughter, who donated his images to the National World War I Museum. Photo: Turkish army, including cavalry, infantry and artillery. (Photo by Dr. P.A. Smithe/National World War I Museum, Kansas City, Mo.)

A rider on horseback competes in the Margalla Festival Tent Pegging Championship in Islamabad, Pakistan, June 5, 2016. Tent pegging is an equestrian sport popular in India and Pakistan, with a history going back to the cavalries of ancient armies. (Photo by Caren Firouz/Reuters)

Three prostitutes lean out of a window in Santiago, Chile, in an attempt to entice customers inside, circa 1950. (Photo by Three Lions/Getty Images)

The Photographers 2015 runs from 25 November to 23 December at Osborne Samuel and Beetles+Huxley, London. Here: Untitled, 1950, by Bert Hardy. (Photo by Bert Hardy/Beetles+Huxley & Osborne Samuel)

The last American military convoy to depart Iraq from the 3rd Brigade, 1st Cavalry Division crosses over the border into Kuwait on December 18, 2011 in Khabari Al Awazeem, Kuwait. (Photo by Mario Tama/Getty Images)

In this September 30, 2013 photo, farmers wait for customers next to their 1950s Chevrolet loaded with garlic for sale at the 114th Street Market on the outskirts of Havana, Cuba. The market s bustle is a result of economic reforms begun in 2010 by President Raul Castro, which includes relaxing rules on private farming. (Photo by Ramon Espinosa/AP Photo)

North Koreans perform during the “Arirang” Mass Games at the May Day Stadium in Pyongyang, as part of celebrations ahead of the 60th anniversary marking the end of the 1950-53 Korean War, in this photo taken by Kyodo July 22, 2013. (Photo by KYODO)