For 37 years, I worked for Hq NORAD, which defends the U.S. and Canada. James Irwin also worked there in the US Air Force before he became an astronaut. He is now deceased and I am helping his family continue his legacy.
This 1970 movie's story is based on the 1864 massacre at Sand Creek, near Eads in southeastern CO. I have seen the Colorado History Museum's video about this event. The Colorado Militia led by Gen Chivington (Gen Iverson in the movie), attacked this peaceful Cheyenne village in southern Colorado in retaliation for a Cheyenne Indian attack in northern Colorado near Julesburg. My great-grandmother was 7 years old when she witnessed Chivington's parade of Indian body parts and dead babies on swords down the main street of Denver--a horrible sight she never forgot and retold throughout her long life. Several soldiers refused to participate in the genocide and mutilations; they filed formal complaints in Colorado and Washington, DC. For that, they were eventually murdered by some of their fellow soldiers. Senator Ben Nighthorse Campbell of Colorado finally got the Sand Creek Massacre site designated as a National Historical Site in 2007. Of course this movie is done by Hollywood and has it's own plot, but the ending is definitely accurate. It was not advertised in Colorado--mostly sold in Canada and the UK--hard to ever find a copy until after 2000. If you want to feel better after viewing this movie, watch "Last of the Dog Men."