Action Comics #241

Superman strains under the weight of an enormous golden key — a lock-opener so massive the cover's caption warns it would take one hundred men to lift it — yet someone has managed to use it on the heavy vault door of Fort Superman, set against a dramatic icy landscape. This June 1958 issue of Action Comics poses a genuinely intriguing mystery right on its cover, with the story title "The Super-Key to Fort Superman" promising a tale centered on the Man of Steel's most secret refuge. Cover pencils by Curt Swan and inks by Stan Kaye bring a satisfying sense of scale and tension to the scene, with Superman's determined expression making it clear he takes this breach of his fortress very seriously.