You Can't Take The Iron Sky From Me
Mars was the first human colonized world. After few hundred years the humans found a temple beneath the surface. This reversed a phase shift that held all the other races and the environment for mars out of sight. After many many misunderstandings the races worked well together till the fallout of Jupiter.
Recently Mars rose up in revolt against the Techno Nazi. The Techno Nazi put down the revolt a few years ago and mars is under martial law.
Deimos and Phobos are also colonized