The US army committed a massacre against the villages of Cheiene and Arapaho in Sand Creek. The members of these countries of origin were holding a peaceful meeting, when they were attacked by American soldiers. About 200 unarmed people were maimed and killed, of whom about two-thirds were children and women.

The conflicts began when they bought the lands of the indigenous peoples of Colorado and sent them to reserves, and the massacre destroyed the power structure of the Txeiene tribes.