In this Thursday, December 1, 2016 photo, Cat Bigney, part of the Oglala Native American tribe, waits on the shore of the Cannonball river for travelers to arrive by canoe at the Oceti Sakowin camp where people have gathered to protest the Dakota Access oil pipeline in Cannon Ball, N.D. So far, those at the camp have shrugged off the heavy snow, icy winds and frigid temperatures. But if they defy next week's government deadline to abandon the camp, demonstrators know the real deep freeze lies ahead. Life-threatening wind chills and towering snow drifts could mean the greatest challenge is simple survival. (Photo by David Goldman/AP Photo)

Japanese college students look at cheerleaders during a job-hunting rally in Tokyo January 29, 2014. According to the rally organizers, about 1,500 students from vocational schools attend the rally to boost their morale ahead of their job hunt. (Photo by Yuya Shino/Reuters)

A girl paddles on her stand-up board on the waters of Guanabara bay at Bica beach in Rio de Janeiro Brazil, January 10, 2016. Few features capture the beauty, or the problems, of one of the world's most dramatic urban landscapes like Guanabara Bay - the finger-like inlet that forms the shoreline and harbor for Rio de Janeiro. The bay, which carves into southeast Brazil from the Atlantic Ocean, literally gave Rio its name when Portuguese mariners mistook it for a “rio”, or “river”. Four centuries later, the bay is preparing to welcome another sort of seafarer – Olympic sailors, who will navigate the bay when the 2016 Rio Olympics kick off in August. (Photo by Ricardo Moraes/Reuters)

Adventurer Sam Cossman movies towards the huge lava lake wearing a custom built industrial proximity heat suit on December 20, 2014 in Ambrym, Vanuatu. (Photo by Conor Toumarkine/Barcroft Media)

A tourist poses on the glass-bottom bridge at Zhangjiajie Grand Canyon on August 20, 2016 in Zhangjiajie, Hunan Province of China. The Zhangjiajie Grand Canyon's glass-bottomed bridge welcame its trial operation on Saturday and about 8,000 tourists crowded to view the grand glass bridge. (Photo by VCG/VCG via Getty Images)

A climber walks on the ridge beneath the eastern peak of the Gamsberg (2385 meters above sea level) near Grabs, Switzerland, Friday, October 3, 2014. (Photo by Gian Ehrenzeller/AP Photo/Keystone)

Deputies in the Ukrainian parliament brawled in the chamber on Tuesday, April 8, 2014 after a communist leader accused nationalists of playing into the hands of Russia by adopting extreme tactics early in the Ukrainian crisis. Two deputies from the Svoboda far-right nationalist party took exception to the charges by communist Petro Symonenko and seized him while he was talking from the rostrum. (Photo by Valentyn Ogirenko/Reuters)

Lightning illuminates a thundercloud as a storm front hits the North Sea region near Westerhever, northern Germany, on August 11, 2014. (Photo by Daniel Reinhardt/AFP Photo/DPA)