A couple looks at their flooded street from behind their home's window in La Plata, in Argentina's Buenos Aires province, where at least 35 people were killed by flooding overnight, on April 3, 2013. (Photo by Natacha Pisarenko/Associated Press)

14 week-old twin polar bear cubs play during their first presentation to the media in Hellabrunn zoo on March 19, 2014 in Munich, Germany. The male and female twins were born on December 9, 2013 in the zoo. (Photo by Alexandra Beier/Getty Images)

An excavator removes a dead bear at the zoo in Tbilisi, Georgia, June 17, 2015. Tigers, lions, bears and wolves were among more than 30 animals that escaped from a Georgian zoo and onto the streets of the capital Tbilisi on Sunday during floods that killed at least 12 people. REUTERS/David Mdzinarishvili

The “Yama” (Pit) memorial is seen in the centre of Minsk May 5, 2015. The memorial is dedicated of the destruction of the Minsk ghetto during World War Two, when several hundred thousands of Jews were slaughtered. Belarus will mark Victory Day on May 9, the 70th anniversary of the Soviet Union's victory over Nazi Germany. (Photo by Vasily Fedosenko/Reuters)

An Afghan man is carried out of a hospital after receiving treatment following a suicide truck bomb attack in Kabul, Afghanistan August 7, 2015. The bombings were the first in Kabul since Mullah Akhtar Mansour took charge of the Taliban last week, and followed a rare truck bomb attack in an eastern province on Thursday. (Photo by Omar Sobhani/Reuters)

A sauna building sits above the clouds at 9,280 feet (2,752 meters) at the Rifugio Lagazuoi in the Dolomite Mountains near Cortina d' Ampezzo in northern Italy July 17, 2015. The Dolomites are home to the Dolomiti Bellunesi National Park and were declared a UNESCO World Heritage Site in August, 2009. (Photo by Bob Strong/Reuters)

A candle burns during a vigil in Aotea Square to remember victims of the Paris attacks on November 14, 2015 in Auckland, New Zealand. According to reports, over 150 people were killed in a series of bombings and shootings across Paris, including at a soccer game at the Stade de France and a concert at the Bataclan theater. (Photo by Hannah Peters/Getty Images)

A house burns as the Butte fire rages through Mountain Ranch, California September 11, 2015. Evacuation orders were expanded to thousands of homes in northern California's Sierras on Friday as the rapidly spreading wildfire roared for a third day through drought-parched timber and brush, threatening mountain communities. (Photo by Noah Berger/Reuters)