CHALLOCK, ENGLAND - MARCH 31: Tony Hall walks with his dog through an installation entitled 'Super Kingdom', which hangs in trees in King's Wood as part of the Stour Valley Arts project on March 31, 2011 in Challock, England. The works by artists Bruce Gilchrist and Jo Joelson of 'London Fieldworks' consist of a series of interesting animal habitats, modelled on the palaces of Stalin, Ceauscescu and Mussolini, and offer nesting sites to many native and migrant species. (Photo by Dan Kitwood/Getty Images)

Construction continues on One World Trade Center (TALLEST BUILDING AT LOWER LEFT) as the memorial footprints of the twin towers are seen (BOTTOM C) on August 12, 2011 in New York City. Upon completion, One World Trade Center will be New York's tallest skyscraper, topping out at a symbolic 1,776 feet, with 3 million square feet of office space. More than 2,700 people were killed when al-Qaeda terrorists hijacked U.S. passenger jets and flew them into the twin towers of the World Trade Center on September 11, 2001. Nearly ten years after the crippling attacks on Lower Manhattan, business, tourism and new construction like One World Trade Center have rejuvenated the formerly devastated cityscape.(Photo by Mario Tama/Getty Images)

Street fighting in Berlin between Government troops and Spartacists, during the Spartacist uprising which followed Germany's defeat in World War I. (Photo by Keystone/Getty Images). 1919

Female pilot Anna climbs out the cockpit of Japanese electronics company Suidobashi Heavy Industry's newly unveiled robot “Kuratas” at the Wonder Festival in Chiba, suburban Tokyo on July 29, 2012. The “Kuratas” robot, which will go on sale with a price tag of one million USD, measures four meters in height, weighs four tons and has four wheeled legs that can either be controlled remotely through the 3G network or by a human seated within the cockpit. (Photo by Yoshikazu Tsuno/AFP Photo)