Young girls practice acrobatic skills in the Sichuan Provincial Art School July 14, 2008 in Chengdu of Sichuan Province, China. (Photo by China Photos/Getty Images)

A chimp motions for Santa to deliver his gift during Lion Country Safari's annual Christmas with the Chimps on Thursday, December 20, 2012. (Photo by Bruce R. Bennett/The Palm Beach Post)

Bikers passes along the High Street on March 18, 2012 in Royal Wootton Bassett, England. The ride, in its third and final year and involving thousands of bikers started at Hullavington airfield and aims to honour the people of Royal Wootton Bassett and to raise money for the Afghan Heroes charity. (Photo by Matt Cardy/Getty Images)

The “Naked Cowboy” plays his guitar in Times Square on March 23, 2012 in New York City. A recent study found that the Times Square district contributes up to 10% of all jobs in the city and is responsible for approximately 11% of economic activity. (Photo by Andrew Burton/Getty Images)

Musician Lenny Kravitz and actress Demi Moore attend Chanel beachside BBQ celebrating Art.sy at Soho Beach House on December 5, 2012 in Miami Beach, Florida. (Photo by Venturelli/WireImage)

An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)