Comics are known to toy with the idea of different realities, and this can yield some powerful results in the end. One of DC's greatest examples of an altered continuity is with Flashpoint. In this story, Barry Allen can no longer take the grief of losing his mother and goes back in
time to save her. In the process, though, he changes so much about the future that he not only loses his powers, but nearly destroys the world in the process.
Flashpoint pitted Aquaman and Wonder Woman against each other- both of them with separate armies that were at war with another and placed the Earth as their battlefield. Meanwhile, there were a group of rebels including the likes of Grifter, Shazam, and Etrigan that sought to stop the war altogether. Together with a much different Batman, the Flash even formed a de facto version of the Justice League that intervened in this war as well. All of the battles together culminated in one of the most tense finales known to comic history, which all ends with Barry running as fast as he can. Makes you think less of that one episode of Flashpoint that the CW did, huh?