Wounded Knee Massacre as one of a series of events ahead of the US expansionist policy of settling white people, and the expulsion of the Indians and their accommodation in reservations. Thus, over a hundred Indians, who were fleeing from American troops, were killed in this massacre. Apparently, the US authorities were upset by Ghost Dance performed by the Indians, as a war dance for religious awakening and the return and renewal of their old world before the arrival of the white man.
The answer is: Wounded Knee.