A new monorail service in Houston, Texas, ready for its inaugural service. (Photo by Evans/Three Lions/Getty Images). Circa 1950

A British woman plays a piano designed especially for people who are confined to bed. Date: 1935. (Photo by Mary Evans Picture Library/Caters News)

Hitler, Hirohito and Mussolini, in effigy, are about to take a mile-high plunge over Stone Mountain, near Atlanta, Georgia, June 21, 1942, as part of the scrap rubber drive. Private Elias Nour, who arranged the stunt as a farewell party on the eve of his entrance into the army, is on the running board. He guided as the “Axis” plunged to destruction. Spectators had to give a scrap of rubber as the price of admission to the spectacle. (Photo by AP Photo)

Princess Diana relaxes on the sand during a visit to the beach on the Caribbean Island of Nevis January 4, 1993. (Photo by Mark Cardwell/Reuters)

N.C. Dezendorf, wife of the general manager of the Electro-Motive division of General Motors, christens the new lightweight “Aerotrain” at the company's locomotive works in La Grange, Ill. on August 22, 1955. (Photo by Edward Kitch/AP Photo)

New Orleans police officers try to keep their heads down as they move in on a Black Panther headquarters during an exchange of gunfire in New Orleans on September 15, 1970. The shootout occurred as police moved in to make arrests on Tuesday morning following a series of incidents. (Photo by Jack Thornell/AP Photo)

(L-R) Playmate Victoria Silvstedt, Donald Trump and Melania Knauss at the Playboy 50th Anniversary celebration December 4, 2003 in New York City. (Photo by Peter Kramer/Getty Images)

Prince Philip, the Duke of Edinburgh meets members of the cast of “Chicago” during a visit to the Adelphi Theatre in this March 4, 1999 file photo in London, England. (Photo by Anwar Hussein/Getty Images)