Justice League of America #46

In "Crisis Between Earth-One and Earth-Two!", the Justice League of America confronts a bizarre rift between two parallel worlds as citizens—including Blockbuster and Solomon Grundy—begin vanishing from one reality and reappearing in the other. Written by Gardner Fox and illustrated by Mike Sekowsky, with inks by Sid Greene and letters by Gaspar Saladino, this landmark 1966 issue reveals the Spectre's grim warning: the arrival of the Anti-Matter Man threatens to destroy both Earths. The cover by Mike Sekowsky and Joe Giella captures the escalating tension of this multiversal crisis.