Asteroid M (X-Men: Evolution)

Asteroid M was the base in which Magneto tried to originally create "a new world".

History
Magneto used the asteroid as a sanctuary to all mutants that won his battles. He also used the asteroid as a place to store captured comatose mutants and transform mutants with his machine he developed. After the X-Men and Brotherhood arrived at his base, Asteroid M was destroyed. Thus, causing Magneto to have to find a new place for an army.