In the 1860s, tensions in colorado between american indians and white settlers led to a massacre at little bighorn. sand creek. wounded knee. pike’s peak.

Sand Creek

Explanation:

From the early 1860s until the late 1870s, the frontier raged with Indian  wars. In 1864, Colorado’s governor persuaded most of the warring Indians in  his territory to gather at Fort Lyon, on Sand Creek, where they were promised  protection.But like many other cases of settlers brutality against indigenous people that was only a disguise. Colonel John M. Chivington's used a white flag to fool a peaceful Indian camp and his 675-man force to massacre a number around of 200 Indians.

the answer is

they were all fought in the middle east during ww1