13. Barry Allen Wasn't The First Flash
Before Barry Allen entered the scene, The Flash was introduced as Jay Garrick, a college student who inhaled gases from hard water experiments and became a living embodiment of the speed god Mercury as a result. Introduced in 1940, he was the first Flash to ever get running, but would be replaced by Barry Allen a little over a decade later. Shown to be a member of the Justice Society of America, Jay returned to the DC Universe with an aged appeared as a mentor of sorts to The Flash and his family. It was revealed that he lived on a parallel Earth (Earth-2), technically making Barry the actual DC Universe's first Flash.