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)

Bollywood actress Chitrashi Rawat lies in a plastic drum as she is briefed by a crew member during the shoot for the film “Black Home” at a beach on the outskirts of Mumbai April 26, 2013. (Photo by Danish Siddiqui/Reuters)

A mass pillow fight in Trafalgar Square in central London on April 5, 2014 on International Pillow Fight Day. (Photo by Jane Scanlan)

A participant takes part in a zombie parade during the Brussels International Fantastic Film Festival in Brussels, Belgium, April 9, 2016. (Photo by Yves Herman/Reuters)

Singer Halsey has her dress adjusted before she poses during the premiere of the film “The Huntsman: Winter's War” in Los Angeles, California, April 11, 2016. (Photo by Kevork Djansezian/Reuters)

Sumo wrestlers compete during the annual “Honozumo” ceremonial sumo tournament dedicated to the Yasukuni Shrine in Tokyo, Japan, April 18, 2016. (Photo by Yuya Shino/Reuters)