An elephant enjoys its back being scrubbed by the keeper on March 1, 1950. (Photo by Fox Photos/Getty Images)

A protester aims a sling shot at police in Santiago, Chile, September 1989. (Photo by Marco Ugarte/AP Photo)

American actress Shelley Duvall poses for photographers at the 30th Cannes Film Festival in France, May 27, 1977. Duvall, whose wide-eyed, winsome presence was a mainstay in the films of Robert Altman and who co-starred in Stanley Kubrick's “The Shining”, has died. She was 75. (Photo by Jean-Jacques Levy/AP Photo)

Astronauts Harrison Schmitt (left) and Eugene Andrew Cernan practice taking geological samples at the Kennedy Space Center in Florida, in preparation for NASA's scheduled Apollo 17 lunar landing mission, on August 28, 1972. Schmitt is the Lunar Module Pilot and Cernan is the mission's Commander. They are training for their period of EVA (extravehicular activity) on the Moon. (Photo by Space Frontiers/Getty Images)

Australian comedian Barry Humphries, dressed as his most famous character Dame Edna Everage, modelling a stunning Ascot hat based on the Sydney Opera House on June 15, 1976. (Photo by Wesley/Getty Images)

A Chesterfield Borough Police telephone operator tests a gasmask with built in earpiece and microphone. The telephone service is considered one of the most important links in the coordination of ARP operations and must remain operational during air raids, 12th April 1939. (Photo by Fox Photos/Hulton Archive/Getty Images)

Mercury and Maia, fueled and overhauled, are waiting in the Tay at Dundee, for favorable weather to start the flight to the Cape, a distance of 6,370 miles. The composite machine moored in the Tay River, at Dundee, on September 23, 1938. (Photo by AP Photo)

Mr. Grindell Matthews with his latest invention, the new photographic gun which is the latest development in sky signs. 1933. It can throw a beam of light 15 miles into the sky. (Photo by Fox Photos)