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)

A U.S. Army soldier with the 10th Special Forces Group and his military working dog jump off the ramp of a CH-47 Chinook helicopter from the 160th Special Operations Aviation Regiment during water training over the Gulf of Mexico as part of exercise Emerald Warrior 2011 on March 1, 2011. (Photo by Tech. Sgt. Manuel J. Martinez/U.S. Air Force)

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

A rebel fighter supporter shoots an AK-47 rifle as she reacts to the news of the withdrawal of Libyan leader Muammar Gaddafi's forces from Benghazi March 19, 2011. The conflict was sparked by clashes in Benghazi and escalated into a rebellion that spread across the country. Gaddafi was captured and killed on October 20, 2011. Libya is currently caught up in a conflict between two rival factions who once battled together against the late Libyan leader. (Photo by Goran Tomasevic/Reuters)

Brad Snead walks past melting ice on the Cook Inlet beach, Saturday, March 26, 2011, in Kenai, Alaska, while looking for agates. (AP Photo/Peninsula Clarion, M. Scott Moon)

Miranda Kerr poses at the David Jones Spring/Summer fashion preview on Burke Street on August 10, 2011 in Melbourne, Australia. (Photo by Lucas Dawson)

Protestors affiliated with the Occupy Wall Street movement block the entrance to the Iowa Democratic Party headquarters during a protest on December 29, 2011 in Des Moines, Iowa. Thirteen people were arrested during the protest. (Photo by Andrew Burton/Getty Images)

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)