In Comics
Amazing Spider-Man #9 (February, 1964)
The X-Men #49 - Who Dares Defy The Demi-Men?
Base
-
Serval Industries, Virginia; formerly X-Factor Investigations Headquarters, Starjammer; Xavier Institute for Higher Learning, Salem Center, Westchester County, New York; Genosha; X-Factor HQ, Washington D.C., Maryland; Mutant Research Center, Muir Island;