Displaced Sunni people, who fled the violence in the city of Ramadi, arrive at the outskirts of Baghdad, April 17, 2015. Iraqi security forces fought Islamic State militants at the gates of the western city of Ramadi on Friday, and local authorities warned it was in danger of falling unless reinforcements arrived soon. (Photo by Reuters/Stringer)

A man is silhouetted in front of the Allianz-Arena as he walks his dogs at sunrise in Munich, southern Germany, Friday, April 10, 2015. (Photo by Peter Kneffel/AP Photo/DPA)

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)

Women dance during the traditional Feria de Abril (April fair) in the Andalusian capital of Seville, southern Spain, April 21, 2015. The fair will run until April 26. (Photo by Marcelo del Pozo/Reuters)

Lioness and hyena posture to one another, in Masai Mara, Kenya, August 2015. A photographer captured one of the oldest rivalries in the animal kingdom as a pair of lions went head to head with a pack of hungry hyenas. (Photo by Ingo Gerlach/Barcroft Images)

English singer-songwriter, dancer, model and actress Sarah Harding attends the launch of Walkers Bring It Back Campaign at Vinopolis on September 3, 2015 in London, England. (Photo by Joseph Okpako/WireImage)

This photo provided by Joan Marcus on August 28, 2015 shows ballerina Misty Copeland in the musical “On the Town” at the Lyric Theatre in New York. Until September 6, 2015 Copeland will play Miss Turnstiles, a love interest for one of three sailors enjoying a few hours of shore leave in 1940s New York. (Photo by Joan Marcus via AP Photo)

The Soyuz TMA-18M spacecraft is transported from an assembling hangar to its launch pad at the Baikonur cosmodrome, Kazakhstan, August 31, 2015. The Soyuz is scheduled to blast off with Aidyn Aimbetov of Kazakhstan, Sergei Volkov of Russia and Andreas Mogensen of Denmark to the International Space Station (ISS) on September 2, 2015. (Photo by Shamil Zhumatov/Reuters)