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)

Justin Beiber unveils his waxwork at Madame Tussauds on March 15, 2011 in London, England.

A woman surveys the damage after the earthquake on March 17, 2011 in Kensennuma, Japan. (Photo by Chris McGrath/Getty Images)

Penny Farthing cyclists ride near Tower Bridge on June 9, 2011 in London, England. The riders have cycled from Paris ahead of the IG Markets London Nocturne cycling event on June 11, 2011. (Photo by Peter Macdiarmid/Getty Images)

Monsoon thunderstorm in Sierra Vista, Arizona. 9 Sept, 2011. (Photo by Steven Maguire)

The sun shines on Weston-super-Mare's Sand Sculpture Festival and the sand art currently being displayed on July 4, 2011 in Weston-Super-Mare, England. Now in its fourth year and with a Amazon Jungle theme for 2011, the seaside resort's event attracts top sand sculptors from across the world and runs throughout the summer months. (Photo by Matt Cardy/Getty Images)

Bonhams expert Michaela Vergottis holds a yellow Jade Chinese Imperial Sceptre on May 9, 2011 in London, England. The piece which is thought to have been taken by British Troups during the Boxer Rebellion is expected to fetch between £800,000 – 1.2 M GBP when it goes on sale at the “Chinese Art” sale at Bonham's auction house on May 12, 2011. (Photo by Dan Kitwood/Getty Images)