A burning train wagon is seen after an explosion at Lac Megantic, Quebec, July 6, 2013. A large swath of Lac Megantic was destroyed Saturday after a train carrying crude oil derailed, sparking several explosions and forcing the evacuation of up to 1,000 people. (Photo by Mathieu Belanger/Reuters)

Timbuktu: A UN peacekeeper from Burkina Faso stands guard at the Djinguereber mosque, built in the 14th century, during a visit by a UN delegation on election day in Timbuktu, Mali, July 28, 2013. (Photo by Joe Penney/Reuters)

Clearing skies await a tripod-toting photographer looking for a spot to capture the early-morning light at Portland Head Light, Thursday, January 17, 2013, in Cape Elizabeth, Maine. (Photo by Robert F. Bukaty/AP Photo)

Members of the Coney Island Polar Bear Club warm up before swimming at the beach at Coney Island in New York, December 15, 2013. (Photo by Eric Thayer/Reuters)

An Oakland Raiders cheerleader performs during the second half of an NFL football game against the Pittsburgh Steelers in Oakland, Calif., Sunday, October 27, 2013. (Photo by Marcio Jose Sanchez/AP Photo)

A grave cleaner holds up a skull during exhumation works at the Cemetery General in Guatemala City May 24, 2013. If a lease on a grave has expired or not been paid, grave cleaners will break open the crypts to remove and rebury the bodies. (Photo by Jorge Dan Lopez/Reuters)

A view of an installation as part of the “S.A.C.R.E.D” exhibition by Chinese artist Ai Weiwei during the 55th La Biennale of Venice, in the church of Sant'Antonin in Venice May 28, 2013. (Photo by Stefano Rellandini/Reuters)

Elephants munch on Christmas trees in their enclosure at Berlin's Zoologischer Garten Zoo on January 4, 2013 in Berlin, Germany. Traditionally, the animals get in the first week of the year leftover Christmas trees. (Photo by Andreas Rentz)