A baby hippo swims under the water in its enclosure at Prague Zoo, Czech Republic, February 24, 2016. The baby was born on January 28, and is yet to be named. (Photo by David W. Cerny/Reuters)

Female Kurdish Peshmerga take part their graduation ceremony at a police academy in Zakho district of the Dohuk Governorate of the Iraqi Kurdistan province, Iraq March 30, 2016. (Photo by Ari Jalal/Reuters)

A woman reacts as she attends a funeral ceremony for Mykola Kuliba and Serhiy Baula, servicemen from the “Aydar” battalion, who were killed in the fighting in eastern Ukraine, at Independence Square in central Kiev, Ukraine, May 26, 2016. (Photo by Gleb Garanich/Reuters)

Women wearing kimonos gather after attending a Coming of Age ceremony on January 8, 2018 in Yokohama, Japan. Coming of Age Day is a Japanese holiday held every January to celebrate people who have reached 20 – the official age of adulthood in Japan. Yokohama city, with almost 37,000 people turning 20 this year, is holding one of the largest events in the country. (Photo by Carl Court/Getty Images)

American Paralympic snowboarder Amy Purdy dances with a robot during the opening ceremony of the Rio 2016 Paralympic Games at the Maracana stadium in Rio de Janeiro on September 7, 2016. (Photo by Yasuyoshi Chiba/AFP Photo)

Fireworks explode over the Quadriga statue atop the Brandenburg Gate on New Year's Eve on January 1, 2012 in Berlin, Germany. According to the media, up to one million people celebrate the country's biggest New Year's Eve Party. (Photo by Andreas Rentz/Getty Images)

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)

A model performs on the Toyota FV2 concept car during the 2014 Beijing International Automotive Exhibition at China International Exhibition Center on April 21, 2014 in Beijing, China. More than 2,000 automotive enterprises from 14 countries and regions participated in the 2014 Beijing International Automotive Exhibition from April 20 to April 29. (Photo by Feng Li/Getty Images)