A girl allows a butterfly to be placed on her nose at the Sensational Butterflies exhibition at the Natural History Museum on April 6, 2011 in London, England. The exhibition is divided up into five sensory zones exploring how butterflies see, hear, taste, smell and touch. The display containing hundreds of butterflies runs from April 12 to September 11, 2011. (Photo by Peter Macdiarmid/Getty Images)

A rebel fighter celebrates as his comrades fire a rocket barrage toward the positions of troops loyal to Libyan ruler Muammar Gaddafi April 14, 2011 west of Ajdabiyah, Libya. Rebels exchanged artillery and rocket fire with loyalist troops west of Ajdabiyah April 14 as the confict engulfing Libya continued. (Photo by Chris Hondros/Getty Images)

Plastinated human corpses posed to look like poker players stand on display at the Body Worlds exhibition on April 27, 2011 in Berlin, Germany. The exhibition, which features human and animal corpses plastinated by Gunther von Hagens, focuses on the role of the heart. It will be open to the public at the Postbahnhof from April 27 to August 14. (Photo by Sean Gallup/Getty Images)

A woman and a child make a bonfire at a makeshift camp for migrants and refugees at the Greek-Macedonian border near the village of Idomeni, Greece, April 1, 2016. (Photo by Marko Djurica/Reuters)

Men dressed as women kiss as they take part in a parade during the Popo (Mask) Carnival of Bonoua, east of Abidjan, April 9, 2016. (Photo by Luc Gnago/Reuters)

A Pakistani vendor tries to salvage materials after flood water destroyed his shop following heavy rain on the outskirts of Peshawar on April 4, 2016. (Photo by A. Majeed/AFP Photo)

Ultra-Orthodox Jewish men prepare matza, traditional unleavened bread eaten during the upcoming Jewish holiday of Passover, in the southern city of Ashdod April 17, 2016. (Photo by Amir Cohen/Reuters)

A newly born Indian white tiger cub yawns in its enclosure at Liberec Zoo, Czech Republic, April 25, 2016. (Photo by David W. Cerny/Reuters)