What fictional universe is aired on the CW for The Flash?
Arrowverse The Arrowverse is a shared fictional universe that is centered on television series airing on The CW, developed by Greg Berlanti, Marc Guggenheim, Andrew Kreisberg, Phil Klemmer, and Geoff Johns, based on characters appearing in publications by DC Comics. The shared universe, much like the DC Universe in comic books or the cinematic DC Extended Universe, was established by crossing over common plot elements, settings, cast, and characters. The Arrowverse stars Stephen Amell as Oliver Queen / Green Arrow, Grant Gustin as Barry Allen / Flash, Megalyn Echikunwoke as Mari Jiwe McCabe / Vixen, with an ensemble cast leading "Legends of Tomorrow", including Arthur Darvill as Rip Hunter, Caity Lotz as Sara Lance / White Canary, Brandon Routh as Ray Palmer / Atom, Dominic Purcell as Mick Rory / Heat Wave, with Victor Garber and Franz Drameh as Martin Stein & Jefferson "Jax" Jackson / Firestorm. Russell Tovey stars as Ray Terrill / The Ray.
Earth-One Earth-One (also Earth-1) is a name given to two fictional universes (The Pre-Crisis and Post-Crisis versions of the same universe) that have appeared in American comic book stories published by DC Comics. The first Earth-One was given its name in "Justice League of America" #21 (August 1963), after "The Flash" #123 (September 1961) explained how Golden Age (Earth-Two) versions of characters such as the Flash (Jay Garrick) could appear in stories with their Silver Age counterparts (Barry Allen). This Earth-One continuity included the DC Silver Age heroes, including the Justice League of America. Earth-One, along with the four other surviving Earths of the DC Multiverse, are merged into one in the 1985 miniseries "Crisis on Infinite Earths". This Earth's versions of characters were primarily the Earth-One versions (i.e. Superman, Batman), but some characters from the four other worlds were also "folded" in. In "Infinite Crisis", Earth-One was resurrected and merged with the primary Earth of the publication era to create a New Earth that brought back more aspects of Earth-One's original history. In 2007, a new version of Earth-One was created in the aftermath of events that occurred within the " 52" series.