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)

In this Friday, March 13, 2015, Mitch Seavey's lead dogs with frosty whiskers at the Huslia, Alaska, checkpoint for the Iditarod Trail Sled Dog Race. (Photo by Loren Holmes/AP Photo/Alaska Dispatch News)

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)

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)

An Orthodox activist (Right) clashes with a gay rights campaigner during a protest outside of the State Duma, Russian Parliament's lower chamber, in downtown Moscow, January 22, 2013. (Photo by Ilya Pitalev/RIA Novosti)

Richard Silver's photographs show us the world's biggest sights like Machu Picchu in Peru or Copacabana in Brazil. His photos, however, are not simply depictions of the landmarks but planned, artistic visual constructions that, with their playful combinations of sharpness and blur, create new worlds of experience. Photo: Coliseum, Rome. (Photo by Richard Silver)

Men stroll past roadside vendors as a painted truck makes its way through the busy street in Kabul, Afghanistan, November, 1961. (Photo by Henry S. Bradsher/AP Photo via The Atlantic)