A pair of giant pandas play in their enclosure at the Beijing Zoo on June 5, 2012 in Beijing, China. With an estimated 1,600 living in the wild, the endangered giant panda dwell in a few mountain ranges in central China, in Sichuan, Shaanxi, and Gansu provinces. (Photo by Lintao Zhang)

"La Montagna di Sale (The Salt Mountain)" by Mimmo Paladino is displayed in Piazza Duomo on April 5, 2011 in Milan, Italy.

Afghan police recruits undergo training at the Afghan Police Academy October 5, 2010 in Kabul, Afghanistan. (Photo by Majid Saeedi/Getty Images)

A man sledges on Primrose Hill with his daughter and their dog on February 5, 2012 in London, England. The United Kingdom is experiencing heavy snowfall with many areas affected. (Photo by Peter Macdiarmid/Getty Images)

A firefighter battling the King Fire watches as a backfire burns along Highway 50 in Fresh Pond, California September 16, 2014. The fire led officials to call on about 400 people to evacuate from areas threatened by the blaze, Cal Fire spokeswoman Alyssa Smith said. It has charred more than 11,500 acres (4,654 hectares) and was 5 percent contained on Tuesday. (Photo by Noah Berger/Reuters)

Kika-evolution, 5, an Auguste clown, poses for a photo during Mexico’s 17th annual clown convention, La Feria de la Risa, in Mexico City, October 23, 2012. Approximately 500 clowns gathered at two local theaters in the capital city to exchange ideas, compete for laughs and show off their comedy performances. (Photo by Anita Baca/AP Photo)

A Los Angeles County firefighter puts water a burning house in a wildfire in the Lake View Terrace area of Los Angeles Tuesday, December 5, 2017. Ferocious winds in Southern California have whipped up explosive wildfires, burning a psychiatric hospital and scores of other structures. Tens of thousands of people have been ordered evacuated. (Photo by Chris Carlson/AP Photo)

An Indian nomadic shepherd from the western Rajasthan state guides his flock of sheep through an access road in Greater Noida, outskirts of New Delhi, India, Tuesday, December 5, 2017. Looking for suitable pasture lands for grazing, shepherds migrate their flocks over extensive areas in the same state or to neighboring states in India. (Photo by R.S. Iyer/AP Photo)