A sun bear reacts to triple-digit temperatures at the Henry Doorly Zoo in Omaha, Nebraska, where the temperature reached 103 degrees Fahrenheit on July 6, 2012. (Photo by Nati Harnik/Associated Press)

A three-seater Toyota Kikai concept car is displayed during the 2016 CES trade show in Las Vegas, Nevada January 8, 2016. (Photo by Steve Marcus/Reuters)

Model Kendall Jenner poses on the red carpet as she arrives for the screening of the film “Mal de pierres” (From the Land of the Moon) in competition at the 69th Cannes Film Festival in Cannes, France, May 15, 2016. (Photo by Yves Herman/Reuters)

A protester with his face smeared with soot from burning barricades stands in the Musaga neighbourhood of Bujumbura on May 6, 2015. Government and opposition rivals are meeting in Burundi in a bid to end deadly demonstrations against a third term bid by the president, as regional foreign ministers arrived to add pressure. (Photo by Phil Moore/AFP Photo)

The newest Victoria's Secret “Angels” models pose for photographers in New York's Times Square during the launch of the new “Body by Victoria” campaign July 28, 2015. From L-R front row are Elsa Hosk, Martha Hunt, Sara Sampaio, Jasmine Tookes and Stella Maxwell. From L-R back row are Kate Grigorieva, Taylor Hill, Rommee Strijd, Jac Jagaciak and Lais Ribeiro. (Photo by Mike Segar/Reuters)

Models dance during the presentation of Stella McCartney's Spring-Summer 2017 ready-to-wear fashion collection presented Monday, October 3, 2016 in Paris. (Photo by Francois Mori/AP Photo)

People dressed as zombies participate in a parade for World Zombie Day 2016 in London's West End, Britain on October 9, 2016. (Photo by Splash News and Pictures)

Fighters of the Free Syrian Army fire an anti-aircraft weapon in the rebel-held Mashhad area in southeastern Aleppo, on December 12, 2016, as they battle Syrian government forces during an operation to retake the embattled city. The crucial battle for Aleppo entered its “final phase” after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad. (Photo by AFP Photo/Stringer)