Justice League of America #68

This December 1968 issue throws Batman, Green Lantern, Aquaman, Hawkman, and Green Arrow headlong into a confrontation with a massive, dripping, tentacled mass known as the Chaos Maker — and the cover by Dick Dillin and Sid Greene captures the team's desperate charge with real kinetic energy. Five heroes, one monstrous threat looming against a vivid purple background — it's the kind of ensemble image that reminds you why the Justice League concept is so satisfying. Denny O'Neil brings his sharp storytelling sensibility to the title, with Dillin and Greene delivering the dynamic linework that defined DC's Silver Age team books.