A donkey savors warming temperatures after a long winter at the zoo in Warsaw, Poland, on Wednesday, April 8, 2015. (Photo by Czarek Sokolowski/AP Photo)

A migrant boy sits on railway tracks at a train station in Tovarnik, Croatia, September 20, 2015. (Photo by Antonio Bronic/Reuters)

Indian Air Force soldiers toss their rifles as they perform during the full-dress rehearsal for Indian Air Force Day at the Hindon air force station on the outskirts of New Delhi October 6, 2015. (Photo by Anindito Mukherjee/Reuters)

Ruby Rose releases fire at the start of the start of the MTV European Music Awards in Milan, Italy, Sunday, October 25, 2015. (Photo by Luca Bruno/AP Photo)

A woman carries a stone cross in a cemetery in the village of Copaciu, southern Romania, on May 2, 2013. As part of a Holy Week tradition, Romanians visit, on Maundy Thursday, the graves of their loved ones, light fires and share food with community members in memory of the departed. Orthodox worshipers celebrate Easter on May 5. (Photo by Andreea Alexandru/ Mediafax)

British model and actress Rosie Huntington-Whiteley arrives for the Versace's fall-winter 2015/2016 Haute Couture fashion collection presented in Paris, France, Sunday, July 5, 2015. (Photo by Thibault Camus/AP Photo)

An art installation formed with milk churns, made by land art artist Gerard Benoit a la Guillaume, is seen at the Chenau de Mayen in the resort of Leysin, Switzerland August 7, 2015. More than 80 milk churns were placed between the Tour d'Ai and the Tour de Mayen summits at an altitude of 2,000 meters (6,561 feet) above sea level under the direction of the artist, to be photographed for his ongoing art project entitled “Milk churns without borders”. (Photo by Denis Balibouse/Reuters)