CANNON BALL, NORTH DAKOTA - DECEMBER 4: The encampment at Oceti Sakowin camp on the Standing Rock Sioux Reservation has grown to the thousands of people on December 4, 2016 in Cannon Ball North Dakota, Colorado. The US Army Corps of Engineers on Sunday announced they will no longer allow the Dakota Access Pipeline to cross under the Missouri river crossing on the Standing Rock reservation in North Dakota, marking a huge win for Native Americans and protesters who had long opposed the construction. Instead the Army Corps of Engineers will conduct an environmental review and explore alternate routes for the project. (Photo by Helen H. Richardson/The Denver Post via Getty Images)