A three-month-old Sumatran tiger cub named “Bandar” shows his displeasure after being dunked in the tiger exhibit moat for a swim reliability test at the National Zoo in Washington, on November 6, 2013. All cubs born at the zoo must take a swim test before being allowed to roam in the exhibit. Bandar passed his test. (Photo by Manuel Balce Ceneta/Associated Press)

Jack, a Lurcher from Dogs Trust Salisbury, walks past a window display of models in a Dogs Trust shop window in Salisbury, as part of a campaign to discourage the impulse buying of dogs ahead of Valentine's Day, on February 10, 2014. (Photo by Matt Alexander/PA Wire)

A man is silhouetted as he stands on a walkway in the sky lobby at the Chancellery, the seat of German Chancellor Angela Merkel (not pictured) in Berlin, May 7, 2014. (Photo by Thomas Peter/Reuters)

Children surround a man, left, that fell down while walking on a street suspected of having contracted the Ebola virus in the city of Monrovia, Liberia, Tuesday, August 19, 2014. The World Health Organization says the outbreak has killed more than 1,200 people, while authorities struggle to contain its spread and treat the sick. (Photo by Abbas Dulleh/AP Photo)

A child plays beside an idol of the Hindu god Ganesh, the deity of prosperity, the day after it was immersed in the Yamuna river for the Ganesh Chaturthi festival in Delhi, India September 6, 2017. (Photo by Cathal McNaughton/Reuters)

In this September 21, 2017, local villagers repair a fishing boat in Shah Porir Dwip, an island by the Bay of Bengal at Bangladesh’s southern tip. This island can mean both hope and death for the Rohingya Muslims who are desperate to escape the violence that has engulfed their lives in Myanmar’s Rakhine state. High tide or low, day or night, rough waters or calm, when they can find a boat, the Rohingya take their chance to flee to Bangladesh. More than 430,000 have left Myanmar in less than a month. (Photo by Bernat Armangue/AP Photo)

A German special anti-tank gun is ready to fire during the army maneuvers in Silesia, Poland, on September 22, 1928. (Photo by AP Photo)

Kosovo- born British singer and actress Rita Ora performs in Pristina on February 17, 2018 on the occasion of the 10 th anniversary of Kosovo Independence. Kosovo celebrates 10 years since it declared independence, a moment of pride for its ethnic Albanian majority, although sovereignty remains fiercely contested by Serbia. (Photo by Armend Nimani/AFP Photo)