A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)

Female porters carry a holy woman belonging to the Jain community through a street to collect food from local residents living in nearby areas, during early morning in the western Indian city of Ahmedabad December 19, 2014. (Photo by Amit Dave/Reuters)

Locals push a freezer after looting it from a shop, believed to be owned by a foreigner, during service delivery protests in Mohlakeng, west of Johannesburg, February 4, 2015. Local media reported that violence broke out on Wednesday morning when locals barricaded roads and burnt tyres during a service delivery protest. (Photo by Siphiwe Sibeko/Reuters)

Thailand's badminton player Ratchanok Intanon, who hopes to win gold at the Rio Olympics, receives a massage during a morning training session at a gym in Bangkok, Thailand, June 22, 2016. As the humble daughter of factory workers at a Bangkok sweet-maker, badminton was a ticket out of poverty for Ratchanok Intanon, who hopes winning gold at the Rio Olympics might inspire more Thai girls to chase their dreams. (Photo by Athit Perawongmetha/Reuters)

An explosion at a petrochemical plant is seen in Rizhao, Shandong province, July 16, 2015. According to Xinhua News Agency, a fire broke out after the explosion, which was caused by a liquified hydrocarbon leak at the plant, on Thursday morning. There was no report of casualties yet. (Photo by Reuters/China Daily)

Jack London was a prolific photographer in addition to his writing. Here: Salvation Army barracks in London during Sunday morning rush – men who had been given tickets during the night queuing for free breakfast, 1902. (Photo by Jack London/Courtesy of Contrasto)

“Hiding In The Shadows”. This Baby Sandhill taking refuge under Moms wings while sitting on her second egg. I witnessed this baby being born earlier that day,and the next morning saw the other one hatch,what a sight to see. Photo location: Deland, Florida. (Photo and caption by Scott Helfrich/National Geographic Photo Contest)

“Winter shapes, Moscow river”. Moscow river at this part is never covered by ice. When the temperature is very low it's possible to see a strong fog. Morning light and pipes of the oli factory creates a fantastic landscape. Photo location: Moscow, Russia. (Photo and caption by Sergey Rumyantsev/National Geographic Photo Contest)