Warning: The following contains SPOILERS for Supergirl, season 5, episode 9, "Crisis on Infinite Earths - Part 1."
The first chapter of Crisis on Infinite Earths has confirmed that several previously established worlds based on earlier DC Comics movies and television shows are part of the Arrowverse. While this had been hinted by early previews of the long-awaited crossover, the first episode gave viewers their first glimpse at just how extensive the shared universe truly is.
Published in 1985, the original Crisis on Infinite Earths comic book series was a celebration of the richness of DC Comics' history and the company's 50th anniversary. It was also an opportunity for the company to make its books more accessible to new readers, condensing its various alternate realities into a single shared universe. It is expected that the Arrowverse Crisis will do something similar, such as relocating the cast of Supergirl from Earth-38 to Earth-1, where all its other shows are set.
It is unknown just how many worlds may show up over the course of the five-part event, despite several having been confirmed by the Arrowverse showrunners. The only certainty with one-fifth of the event aired is that this truly will be the biggest event in superhero television history. Here is the breakdown of every world now established as part of the Arrowverse.
Earth 89 - Tim Burton's Batman Movies
While we don't get to see Michael Keaton as one rumor suggested, the dark and disturbing world of the Tim Burton's Batman films is represented in one quick cameo, which confirmed it as Earth-89. Danny Elfman's familiar Batman theme plays as the Bat-Signal burns bright in the red skies over Gotham City. This is observed by a man in a trench-coat and fedora, who mutters "I hope you're watching, big guy." The observer is reporter Alexander Knox (Robert Wuhl), who was the first to report upon The Joker's crimes in the 1989 Batman movie.
Earth-9 - DC Universe's Titans
The world of DC Universe's Titans was officially designated as Arrowverse's Earth-9. We briefly see red skies over Titans Tower in San Francisco, before being treated to close-ups of a disturbed looking Hawk (Alan Ritchson) and an upset Jason Todd (Curran Walters). There is a white flash and a fade-to-white suggesting that their Earth may have been destroyed. Thankfully, we know that the Titans will continue on in some fashion, as the series has been renewed for a third season.
Earth-66 - 1966 Batman TV Show
One of the first cameos confirmed for Crisis on Infinite Earths was Burt Ward, who played the Dick Grayson Robin on the 1966 live-action Batman series alongside Adam West's Batman. Ward's cameo is short and sweet, as we see Dick Grayson walking a dog while wearing a red sweater with yellow and green trim suggesting the classic Robin costume. Suddenly, the skies turn red and sinister, prompting the former Boy Wonder to shout "Holy Crimson Skies Of Death!" It isn't a big scene, but it is enough to confirm the 1966 Batman show as the Earth-66 of the Arrowverse.