"Worlds will live. Worlds will die. And the DC Universe will never be the same!"
With those words, DC Comics launched a 1985 mini-series called Crisis on Infinite Earths. If you're a comics reader, I bet you've at least heard of it.
Crisis on Infinite Earths holds a historical place in superhero comics: before Blackest Night, before Age of Apocalypse, before Superman's death and resurrection, this was the first true "Big Event" crossover. It set the paces for every year to come--unfortunately.
Stripped of all its pretenses as an epic, of a series of cool battles with your favorite characters, it is a narrative cleansing and marketing tactic dressed up in mockery of a story.