Superman: At Earth's End #1

It's the 22nd century. Earth has passed through two apocalypses (one occurring in the predecessor, Kamandi: At Earth's End note ). A group of emotionless, logical cyborgs named the Biomech Sevens are overseeing Earth's return to greatness. For the last year, Superman has been regaining his lost strength in a hovering city, where he is able to receive the benefits of the sun's rays. While recuperating, he learns that Gotham City is next in line to be "cleansed", via a nuclear bomb. It has been overrun with mutants and other such degenerates. After battling the Biomech Sevens' leader Ben Boxer, Superman goes down to Gotham, where he is attacked by bat-like mutants that bear a striking resemblance to the Dark Knight and is saved by a mohawked youth biker gang, and finds that the underground of the city houses a fortress where the evil DNA Diktators, who kidnapped the gang's parents and took Bruce Wayne's body from his manor. There he meets the leaders of the Diktators: twin clones of Adolf Hitler!