Participants wear traditional clogs as shepherds lead their sheep through the center of Madrid, October 28, 2012. (Photo by Andres Kudacki/Associated Press)

Indigenous women from the Kamayura tribe take part in a demonstration of Huka Huka fight at the first World Games for Indigenous Peoples in Palmas, Brazil, October 29, 2015. (Photo by Ueslei Marcelino/Reuters)

Heidi Klum attends the Heidi Klum's 16th Annual Halloween Party sponsored by GSN's Hellevator And SVEDKA Vodka At LAVO New York on October 31, 2015 in New York City. (Photo by Mike Coppola/Getty Images for Heidi Klum)

A mother prays for success for her child in the college entrance examinations at a Buddhist temple in Seoul, South Korea, November 12, 2015. About 630,000 students on Thursday sat for the annual exams that could lead them to one of the country's top universities. In South Korea, there is no higher achievement than to be accepted by a prestigious university. As a result, many students prepare for these entrance exams from an early age, often studying up to 16 hours a day for years to take this test. (Photo by Kim Hong-Ji/Reuters)

Members of ASC Tornados, the motorcycle display team of the Indian army, lie in a row on the ground as another performs a stunt by jumping over them during the 225th anniversary celebrations of Army Service Corps in Bangalore, India, Tuesday, December 8, 2015. The Army Service Corps which was established in 1790 is an arm of the Indian Army which handles its logistic support function. (Photo by Aijaz Rahi/AP Photo)

A flight deck crew prepares to launch a F18 Super Hornet from the deck of the USS Eisenhower off the coast of Virginia, December 10, 2015 in the Atlantic Ocean. US Defense Secretary Ash Carter visited the carrier with India's Minister of Defense Manohar Parrikar to demonstrate US Navy aircraft carrier flight operations. (Photo by Mark Wilson/Getty Images)

A Ukrainian serviceman who fought in Debaltseve is seen near Artemivsk February 19, 2015. Fighting raged in eastern Ukraine on Thursday despite European efforts to resurrect a still-born ceasefire, a day after pro-Russian separatists who spurned the truce forced thousands of government troops out of a strategic town. (Photo by Gleb Garanich/Reuters)

A visitor holds up her toy bunny to the aquarium glass in front of Aurora the Russian polar bear at the Sao Paulo Aquarium in Sao Paulo, Brazil, Thursday, April 16, 2015. (Photo by Andre Penner/AP Photo)