Newly commissioned 2nd lieutenants throw their caps in the air as a team of F-16 Air Force Thunderbirds fly over the 2011 graduating class of the U.S. Air Force Academy on May 25, 2011 in Colorado Springs, Colorado. A total of 1,021 graduates received their diplomas in front of their families and dignitaries at the Academy's Falcon Stadium. (Photo by John Moore/Getty Images)

Weakened by sickness and malnutrition, Arbty Mohammad, 2, lies in the Banadir Hospital on August 12, 2011 in Mogadishu, Somalia. Some 100,000 Somalis have flooded into Mogadishu from drought and famine stricken areas of the country. The UN warned Friday that a cholera epidemic could spread through Mogadishu, as Somalis fill unsanitary makeshift camps throughout the capital. (Photo by John Moore/Getty Images)

“Daredevil Nik Wallenda became the first person to walk on a tightrope across the Niagara Falls, taking steady, measured steps June 15, 2012 for 1,800 feet across the mist-fogged brink of the roaring falls separating the U.S. and Canada”. (Photo by John Moore/David Duprey/AP Photo)

People line the streets as a dragon passes by during the Chinese New Year parade on January 29, 2012 in New York City. Thousands of people turned out to see the event which celebrated the Year of the Dragon. (Photo by John Moore/Getty Images)

Mary McHugh mourns her slain fiance Sgt. James Regan at “Section 60” of the Arlington National Cemetery May 27, 2007. Regan, a US Army Ranger, was killed by an IED explosion in Iraq. (Photo by John Moore/Getty Images)

In Omdurman, the largest city in Sudan, the Qadiriyya Sufi order meets every Friday outside Sheikh Hamed Al Nil mosque, which houses the tomb of their 19th century Sufi leader. (Photo by Ala Kheir, John Burns and Ibrahim Algrefwi/Brownbook)

Riot police face off with demonstrators at the “Occupy Denver” camp on October 29, 2011 in Denver, Colorado. Following a march by protesters, police moved in on their encampment to tear down recently erected tents. They arrested numerous protesters, pepper-sprayed others and others reportedly fired rubber bullets at the crowd during the confrontation. (Photo by John Moore/Getty Images)

Occupy Denver protesters dance on an American flag on November 5, 2011 in Denver, Colorado. Hundreds of the demonstrators marched through downtown Denver, denouncing the U.S. Federal Reserve and urging customers to close their accounts with large banks and deposit their funds into local credit unions. (Photo by John Moore/Getty Images)