A steam traction engine with a broken rear axle in Pall Mall, London. (Photo by Topical Press Agency/Getty Images). November 1923

A German special anti-tank gun is ready to fire during the army maneuvers in Silesia, Poland, on September 22, 1928. (Photo by AP Photo)

North Korean youngsters sing and play accordions to entertain foreign visitors including United Nations Secretary General Kurt Waldheim, who visited Pyongyang, May 4, 1979. Visitors report music education in North Korea begins at an early age and is taken seriously by children and adults. (Photo by Peter Arnett/AP Photo)

This 1931 Stutz DV-32 convertible sedan has 66,000 miles on its odometer and its original leather luggage awaits its first complete restoration Tuesday, March 5, 2013 at L'Cars Automotive Specialties in Cameron, Wis. The company which does high-end restoration and customization work classic cars that have won awards at the world-renowned Pebble Beach Concours d'Elegance. Winning cars include a 57c Bugatti, Rolls Royce PIII V12, V12 Aero coupe, T44 Bugatti, T55 Bugatti, T38A Bugatti, Mercedes Benz 290 Roadster, Rolls Royce Silver Ghost, T57 Bugatti, 1929 Duesenberg J, Mercedes Benz 540K cabriolet, Talbot Teardrop and a 1931 V16 Cadillac convertible. (Photo by Mark Hoffman)

A man sits waiting for a train on the London Underground in 1890, when the platform floors were still made from wooden floorboards. (Photo by Hi-Story/Alamy Stock Photo)

A chimpanzee feeding a leopard cub at Southam Park Zoo, Warwickshire. (Photo by Ian Tyas/Keystone Features/Getty Images). 1971

Google has built its first self-driving car prototypes and hopes to test hundreds more models this summer. If all goes well, the company is planning a pilot program in California over the next few years.