Palestinian youths lower their heads as a fellow protester throws back a tear gas canister at Israeli troops during clashes outside Ofer military prison near the West Bank city of Ramallah on May 2, 2012, following a demonstration in solidarity with prisoners held in Israeli jails. Clashes erupted for the second day in a row between stone-throwing youths and the Israeli army near the military jail in the occupied West Bank. TOPSHOTS AFP PHOTO/ABBAS MOMANIABBAS MOMANI/AFP/GettyImages

A vendor covers his head with a basket from the sunlight in Bangkok, Thailand, Thursday, May 3, 2012. (AP Photo/Sakchai Lalit)

2012 Formula One Mugello Test Day, Autodromo Internazionale del Mugello, Mugello, Italy. Formel 1 Testfahrten - F1 - Michael SCHUMACHER, Germany, D, Mercedes GP F1 Team, red light, rain - Copyright: © ATP Jerry ANDRE

A model wearing designs by Jenny Lee stands in a display made of natural props including leaves and branches from native Australian trees, during Australian Fashion Week in Sydney, Thursday, May 3, 2012. (AP Photo/Rob Griffith)

Artist Henry Bruce looks up at his largest, possibly most controversial art project to date, in the grounds of the Delamore Estate. As part of the art and sculpture exhibition at Delamore Henry has painted a massive skeletal 21 metre high oak tree fluorescent pink to celebrate the beauty of nature and the evolving life of trees. Picture date: Wednesday May, 2, 2012. Photo credit should read: Ben Birchall/PA Wire

File photo dated 12/04/12 of Sotheby's staff members hanging The Scream, by Norwegian painter Edvard Munch at the auction house's central London offices. The only privately-owned version of the masterpiece fetched a record-breaking 119.9 million US dollars (£74 million) at auction. Issue date: Thursday May 3, 2012. The famous image, which features a haunted figure in front of a red backdrop, surpassed estimates to become the most expensive work of art to be sold at auction following the sale in New York. See PA story SALE Scream. Photo credit should read: Lewis Whyld/PA Wire

Monkey Swimmers A group of monkeys cool down in the heat by taking a swim in the water in Guiyang, China. They enjoy hanging from the trees and playing around by leaping into the water. China - May 2012 Credit: WENN.com

Fabrice Muamba of Bolton Wanderers shows his emotion after being introduced to the crowd prior to the Barclays Premier League match between Bolton Wanderers and Tottenham Hotspur at the Reebok Stadium on May 2, 2012 in Bolton, England. (Photo by Michael Regan/Getty Images)

A tern feeds on a marsh near the village of Smolichi, 160 km (100 miles) south of Minsk, Belarus, early Thursday, May 3, 2012. (AP Photo/ Sergei Grits)

Newcastle Unied's Papiss Cisse celebrates his goal during the Barclays Premier League match at Stamford Bridge, London. Picture date: Wednesday May 2, 2012. See PA story SOCCER Chelsea. Photo credit should read: Rebecca Naden/PA Wire.