An iCub robot built by the Italian Institute of Technology tracks a ball in the Robotville exhibition at the Science Museum on November 29, 2011 in London, England. The Science Museum's Robotville exhibition showcases 20 unique and cutting-edge robots from European research laboratories, it is free to enter and runs from December 1–4, 2011. (Photo by Oli Scarff/Getty Images)

A girl attends Friday prayers in front of an army tank in Tahrir Square in Cairo February 18, 2011. Five years ago thousands of protesters took to the streets demanding the end of the 30-year reign of President Mubarak as Egypt became the second country to join the Arab Spring. After weeks of clashes, strikes and protests across Egypt, Mubarak resigned on February 11, 2011. (Photo by Suhaib Salem/Reuters)

Archie McQuater, 82-year-old clockmaker at Craiglea clocks, adjusts a clock face to British Summer Time (BST) on March 25, 2011 in Edinburgh, Scotland. Clocks will be put forward by one hour at 1:00 AM GMT on Sunday March 27, 2011 officially the start of British Summer Time. British Summer Time will end this year on October 30. (Photo by Jeff J Mitchell/Getty Images)

A girl allows a butterfly to be placed on her nose at the Sensational Butterflies exhibition at the Natural History Museum on April 6, 2011 in London, England. The exhibition is divided up into five sensory zones exploring how butterflies see, hear, taste, smell and touch. The display containing hundreds of butterflies runs from April 12 to September 11, 2011. (Photo by Peter Macdiarmid/Getty Images)

A Peugeot 408 car is displayed during the 2011 (15th) Shenzhen-Hong Kong-Macao International Auto Show at Shenzhen Convention and Exhibition Center on June 2, 2011 in Shenzhen, Guangdong Province of China. The 6-day Auto Show will be held from June 2 to 7 with total exhibition area of 110,000 square meters. (Photo by ChinaFotoPress/Getty Images)

A Christie's auction house employee wears The Rosebury pearl and diamond tiara, bracelet and brooch on June 6, 2011 in London, England. The jewels, which formerly belonged to Hannah, Countess of Rosebury, feature in Christie's “Important Jewels” sale which take places in London on June 8, 2011. (Photo by Oli Scarff/Getty Images)

A car stands in water on Ferry Road after two magnitude 6.0 and 5.5 earthquakes struck on June 13, 2011 in Christchurch, New Zealand. The aftershocks have followed four months after the major eathquake which hit the city on February 22, 2011 resulting in the deaths of 181 people. (Photo by Martin Hunter/Getty Images)

Senior hurricane forecaster Dr. Jack Beven studies computer models as he tracks Tropical Storm Arlene at the National Hurricane Center on June 29, 2011 in Miami, Florida. Arlene is the first named storm of the 2011 Atlantic hurricane season and is moving at 8 mph, packing sustained winds of 50 mph as it heads towards the east-central coast of Mexico. (Photo by Joe Raedle/Getty Images)