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)

A student shouts slogans against Venezuelan President Nicola Maduro during a protest on the main highway in Caracas on March 30, 2017. Venezuela' s Supreme Court took over legislative powers Wednesday from the opposition- majority National Assembly, whose speaker accused leftist President Nicolas Maduro of staging a “coup”. (Photo by Juan Barreto/AFP Photo)

Ng Sin Nee (L) and Lee Shin May (R) from Malaysia take pictures with the panoramic view of the city from the Sky Box at KL Tower, the world's seventh tallest telecommunications tower, in Kuala Lumpur on May 24, 2016. Officially opened on May 20, the Sky Box has been the latest attraction for tourists arriving to the Malaysian capital. It stands 300 metres above ground and can fit six people at any one time, and offers spectacular views of the Kuala Lumpur skyline, including the iconic Petronas Twin Towers. (Photo by Mohd Rasfan/AFP Photo)

Half-naked girls against speed driving in Nizhny, Novgorod Region, Russia on September 5, 2016. Russian drivers are getting quite an eyeful in a bid to make them slow down thanks to topless women flashing speed limit signs at an accident blackspot. A trial of the road safety campaign demonstrated that it helped lower the speed of traffic near a pedestrian crossing in Severny village. (Photo by YouTube)

Nova Scotia Duck Tolling retriever Torrey competes in the 10th annual Petco Unleashed surfing dog contest at Imperial Beach, California August 1, 2015. Proceeds raised at the event go to benefit the San Diego Humane Society. (Photo by Mike Blake/Reuters)

Then U.S. Army First Lieutenant Kirsten Griest (C) and fellow soldiers participate in combatives training during the Ranger Course on Fort Benning, Georgia, in this handout photograph taken on April 20, 2015 and obtained on August 20, 2015. When Griest and another woman completed the daunting U.S. Army Ranger school this week they helped end questions about whether women can serve as combat leaders, as the Pentagon is poised to open new roles, including elite Navy SEALs, to women in coming months. The feat by Griest and First Lieutenant Shaye Haver followed a re-evaluation of the role of women after their frontline involvement in Iraq and Afghanistan and the end of a rule barring them from combat roles in 2013. (Photo by Spc. Nikayla Shodeen/Reuters/U.S. Army)

Base jumpers leap from the 300-metre high skydeck of Malaysia's landmark Kuala Lumpur Tower against the backdrop of the city's skyline on October 3, 2016 during the annual International KL Tower Base-Jump event. (Photo by Manan Vatsyayana/AFP Photo)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, run at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. Boko Haram says it is building an Islamic state that will revive the glory days of northern Nigeria's medieval Muslim empires, but for those in its territory life is a litany of killings, kidnappings, hunger and economic collapse. (Photo by Afolabi Sotunde/Reuters)