An obstacle course in which the X-Men train appears in The X-Men #1 (September 1963), but the Danger Room is never mentioned by name. The name "Danger Room" is first used in The X-Men #2 (November 1963). According to X-Men writer/editor/co-creator Stan Lee, "the Danger Room was Jack Kirby's idea. I thought it was great because we could always open with an action sequence if we needed to."
