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)

A general view at the launch of Imitate Mordern: A Gallery With A Difference on March 10, 2011 in London, England.

North Korean children wave to people on a Chinese tourist boat on the banks of Yalu River near the Chongsong county of North Korea, opposite the Chinese border city of Dandong, May 8, 2011. (Photo by Jacky Chen/Reuters)

Afghan children play soccer in front of the war-damaged Darul Aman Palace in the suburbs of Kabul, Afghanistan, Wednesday, June 8, 2011. (Photo by Gemunu Amarasinghe/AP Photo)

A man prays to mourn victims of the March 11, 2011, earthquake and tsunami in front of a ship brought ashore by the disaster in Kesennuma, Miyagi Prefecture, Japan. (Photo by Kyodo via 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)