Stargate is a military science fiction media franchise, initially conceived by Roland Emmerich and Dean Devlin, based on the idea of an alien Einstein–Rosen bridge device (the Stargate) that enables nearly instantaneous travel across the cosmos. The franchise began with the film Stargate, released on October 28, 1994, by Metro-Goldwyn-Mayer and Carolco, which grossed US$197 million worldwide. In 1997, Brad Wright and Jonathan Glassner created a television series titled Stargate SG-1 as a sequel to the film. This show was joined by Stargate Atlantis in 2004, and a third spin-off series, Stargate Universe, in 2009. Also consistent with the same story are a variety of books, video games and comic books, as well as the direct-to-DVD movies Stargate: The Ark of Truth and Continuum, which concluded the first television show after 10 seasons.