richard63 wrote:
If I remember correctly, UXM #150 is where Magneto commits his worst crimes -- the sinking of a Russian submarine that kills all aboard, and destroying a Russian town with a volcano.
If you read the captions, it states that Magneto allows the populace of the town to escape, while the actual fate of the sub is left a mystery (it's destruction isn't shown).
Magneto is put on trial for the submarine killings in X-MEN vs. the AVENGERS #4.  (I believe they're also mentioned in UXM #200, but I don't have the issue handy.)