Nickelodeon operates three digital channels separate from the main service: Nick Jr., a channel devoted to preschool programming; TeenNick, aimed at teenagers with mostly live-action programs (which includes a four-hour 1990s block in late night and overnight) and contains some programming that is risque in content; and Nicktoons, which primarily (although not exclusively) runs animated programming. Cartoon Network, launched in 1992, was perhaps the fastest-growing network aimed primarily at children; thanks to extensive support from sister networks TBS and TNT, it became widely popular within five years of its launch. Originally only airing classic animation from the archives of Time Warner (which includes productions from Turner Broadcasting System, Warner Bros., MGM and Hanna-Barbera), it began airing its own original animated programming (Cartoon Cartoons) similar in format to those found on Nickelodeon shortly thereafter.