An artist performs in water during a dress rehearsal for “Amaluna”, a show by Cirque du Soleil, at the Royal Albert Hall in London, Britain January 15, 2016. (Photo by Dylan Martinez/Reuters)

An Indian worker paints the hand of a huge clay model of a tribal woman on the Indian state of Karnataka's tableau for Republic Day parade, in New Delhi, India, Friday, January 22, 2016. Security has been tightened around the Indian capital as well as across the country ahead of Republic Day celebrations, held each year on Jan. 26. (Photo by Manish Swarup/AP Photo)

A model presenting a creation from Andres Sarda's Fall/Winter 2016 collection prepares to pose for a portrait backstage during the Mercedes-Benz Fashion Week in Madrid, Spain, February 21, 2016. (Photo by Susana Vera/Reuters)

Refugees and migrants try to find a place on an already full train headed for Serbia, near the city of Gevgelija, The Former Yugoslav Republic of Macedonia, on February 24, 2016. Refugees and migrants from Iraq and Syria continue to pass through Macedonia on their way to the European Union. (Photo by Georgi Licovski/EPA)

Female of pygmy hippopotamus called Malaya from Netherlands in zoo in Dvur Kralove nad Labem, Czech Republic, February 22, 2016. (Photo by David Tanecek/CTK via ZUMA Press)

A museum employee views “Details of Renaissance Paintings (Sandro Botticelli, Birth of Venus, 1482)” by Andy Warhol at the Victoria and Albert museum in London, Britain, March 2, 2016. The piece forms part of “Botticelli Reimagined”, an exhibition exploring the ways artists have responded to the artistic legacy of the fifteenth century artist Sandro Botticelli, and including over fifty artworks by Botticelli himself. (Photo by Toby Melville/Reuters)

A girl marches alongside Salvadoran soldiers during the parade commemorating Independence Day in San Salvador, El Salvador September 15, 2016. (Photo by Jose Cabezas/Reuters)

Kurdish pesh merga troops fire at Islamic State positions as they move toward the Iraqi town of Badana Pichwk on Monday morning, October 17, 2016. Kurdish forces began Monday advancing on a string of villages east of Mosul, the start of a long-awaited campaign to reclaim Iraq's second-largest city from the Islamic State, which seized it more than two years ago, officials said. (Photo by Bryan Denton/The New York Times)