Read Crisis on Infinite Earths Storyline:
SUMMARY: A mysterious force is moving through reality, destroying all life in its wake. The world's greatest superheroes, Superman, Batman, Wonder Woman, the Flash, and thousands of others are confronted with their greatest challenge: stopping this interdimensional threat before it destroys all life everywhere! To stop this threat, they must ally themselves with the most dangerous super-villains. If they fail, more than 3,000 universes and untold trillions of living beings will die!Pages of Crisis on Infinite Earths :