After a year of struggle, the battle was lost.

Authorities on Thursday cleared a protest camp where opponents of the Dakota Access oil pipeline had gathered for the better part of a year, searching tents and huts and arresting three dozen holdouts who had defied a government order to leave, reported the Associated Press.

It took 3 ½ hours for about 220 officers and 18 National Guardsmen to methodically search the protesters' temporary homes and arrest people, including a man who climbed atop a building and stayed there for more than an hour before surrendering.

Most of the Dakota Access pipeline opponents abandoned their protest camp Wednesday ahead of a government deadline to get off the federal land. Some protesters at Standing Rock burned down structures in the camp as part of a leaving ceremony ahead of the deadline. Here’s a video of the smoldering ruins of the protest site. 

The camp has been home to demonstrators for nearly a year as they tried to thwart construction of the pipeline that is believed to hurt the environment and sacred sites of Native American tribes. 

The pipeline developer, Energy Transfer Partners, began work on the last big section of the oil pipeline this month after the Army gave it permission to lay pipe under a reservoir on the Missouri River. When complete, the pipeline will carry oil through the Dakotas and Iowa to a shipping point in Illinois. As reported in AP and Times magazine.