The X-Files is an American Peabody, Golden Globe and Emmy Award-winning science fiction television series created by Chris Carter, which first aired on 10 September 1993, and ended on 19 May 2002. The show was one of the American FOX network's first major hits, and its main characters and slogans (e.g., "The Truth Is Out There," "Trust No One," "I Want to Believe") became pop culture touchstones. The X-Files is seen as a defining series of the 1990s, coinciding with the era's widespread mistrust of governments, interest in conspiracy theories and spirituality, and the belief in the existence of extraterrestrial life.
In the series, FBI agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) are tasked with investigating the "X-Files": marginalized, unsolved cases involving paranormal phenomena. Mulder plays the role of the "believer", having faith in the existence of aliens and the paranormal, while Scully is a skeptic, initially assigned by her departmental superiors to debunk Mulder's unconventional work. As the show progressed, both agents were caught up in a larger conflict, termed "the mythology" or "mytharc" by the show's creators, and developed a close and ambiguous friendship which many saw more as romantic than platonic. The X-Files also featured stand-alone episodes ranging in tone from horror to comedy, in which Mulder and Scully investigated uniquely bizarre cases without long-term implications on the storyline. These so-called "monster of the week" episodes made up the bulk of the series.
The show's popularity peaked in the mid-to-late 1990s, leading to a theatrical feature film in 1998. In the last two seasons, Anderson became the star as Duchovny appeared rarely, and new central characters were introduced: FBI Agents John Doggett (Robert Patrick) and Monica Reyes (Annabeth Gish). At the time of its final episode, The X-Files was the longest running sci-fi show ever on American television, a title since lost to cable's Stargate SG-1. The show was declared by TV Guide to be the second greatest cult television show (Star Trek being number one) and the 37th best television show of all time. In 2007, TIME magazine included the show on its list of the "100 Best TV Shows of All Time".