Immigrants from the West Indies at Victoria Station in London, 1956. (Photo by Hulton-Deutsch Collection/CORBIS/Corbis via Getty Images)

Two young women embrace in bed together, both wearing white lace underwear. (Photo by Popperfoto/Getty Images)

Couple getting intimate on couch. (Photo by Vincent Besnault/Getty Images)

Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)

A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)

Western lowland gorilla Kijivu holds her newborn baby at the Prague Zoo in the Czech Republic. (Photo by Isifa/Getty Images)

Chinese women ride a bicycle together on a street September 10, 2014 in Beijing, China. (Photo by Kevin Frayer/Getty Images)

A local boy plays football on Iracema Beach on June 11, 2014 in Fortaleza, Brazil. (Photo by Robert Cianflone/Getty Images)