Legends of Tomorrow changed their timeline even before Crisis On Infinite Earths, which Steel remembered thanks to the unlikely help of Rasputin.

A lot has happened in the lead-up to the next Arrowverse crossover. Here's what you need to know before watching Crisis on Infinite Earths.

From marriage to training Superboy, what's Clark Kent been up to between Smallville and Crisis On Infinite Earths?

With Smallville now confirmed as part of the Arrowverse, many want to rewatch the series before Crisis on Infinite Earths. Here's how to do it.