(L-R), Pilot Gregory H. Johnson, European Space Agency astronaut Roberto Vittori, Mission Specialist Greg Chamitoff, Commander Mark Kelly, Pilot Gregory H. Johnson, Mission Specialist Michael Fincke, and Mission Specialist Andrew Feustel, participate in a Terminal Countdown Demonstration Test (TCDT), at the Kennedy Space Center, on April 1, 2011 in Cape Canaveral, Florida. The TCDT will culminate in a full dress rehearsal for the planned April 19th launch of Space Shuttle Endeavour’s final scheduled flight to the International Space Station before being retired. (Photo by Mark Wilson/Getty Images)

Rescuers work at the traffic accident site on April 1, 2011 in Xi'an, Shaanxi province of China. A truck collided with a bus at a cross on Friday morning. As the truck headed for the sidewalk, it collided into a pedestrian and 6 vehicles which were stopped nearby. As a result 16 people were injuried, one currently has severe injuries. (Photo by ChinaFotoPress/Getty Images)

A workman takes a siesta on a girder during the building of Radio City, the city of New York spread out below. (Photo by General Photographic Agency/Getty Images). Circa 1933

Models present creation for the 7th Hosa Cup China Swimwear Design contest and Hosa Swimwear Trend fashion show on day five of China Fashion Week A/W 2011 on March 28, 2011 in Beijing, China (Photo by Feng Li/Getty Images)

A model showcases designs on the catwalk during Beijing Institute of Fashion Technology and Taiwan Shin Chien University Graduates Collection show of China Fashion Week A/W 2011 on March 25, 2011 in Beijing, China. (Photo by Feng Li/Getty Images)

A young arab boy, armed with a rifle and a knife, in the Aden Protectorate near Yemen. (Photo by Richards/Fox Photos/Getty Images). February 1938

Model Adriana Sklenarikova Karembeu presents new “Pikolino” shoes at El Corte Ingles store on April 1, 2011 in Madrid, Spain. (Photo by Carlos Alvarez/Getty Images)

Boys in ceremonial uniform at the civil wedding ceremony of American actress Grace Kelly and Rainier III, Prince of Monaco at the Prince's Palace of Monaco, 18th April 1956. Original publication: Picture Post - 8336 - The Hour Of Marriage - pub. 28th April 1956.