| company =
| theme_music_composer = Joel Goldsmith
| runtime = 43 minutes
| distributor = MGM Television
| creator =
| executive_producer =
| starring =
| country =
| language = English
| network = Sci Fi Channel
| first_aired =
| last_aired =
| num_seasons = 5
| num_episodes = 100
| list_episodes = List of Stargate Atlantis episodes
| preceded_by =
| followed_by =
| related = ''Stargate Universe''
| website = http://stargate.mgm.com/view/series/2/
''Stargate Atlantis'' (often abbreviated ''SGA'') is a Canadian-American adventure and military science fiction television series and part of MGM's ''Stargate'' franchise. The show was created by Brad Wright and Robert C. Cooper as a spin-off series of ''Stargate SG-1'', which was created by Wright and Jonathan Glassner and was itself based on the feature film ''Stargate'' (1994). All five seasons of ''Stargate Atlantis'' were broadcast by the Sci-Fi Channel in the United States and The Movie Network in Canada. The show premiered on July 16, 2004; its final episode aired on January 9, 2009. The series was filmed in and around Vancouver, British Columbia, Canada.
The story of ''Stargate Atlantis'' follows the events of ''Stargate SG-1s seventh season finale episode "Lost City" and eighth season premiere episode "New Order", in which the cast of that series discovered an Antarctic outpost created by the alien race known as the Ancients. In the pilot episode "Rising", Stargate Command sends an international team to investigate the outpost, where Dr. Daniel Jackson discovers the location of Atlantis, the legendary city created by the Ancients, and Colonel Jack O'Neill visits the outpost after having been put in stasis and retrieved from it.
The series was a ratings success for the Sci Fi Channel, and was particularly popular in Europe and Australia. Although it received little critical response, ''Stargate Atlantis'' was honored with numerous awards and award nominations in its five-season run. After ''Stargate Atlantis'' was cancelled, the show's co-creators began working on the already-conceptualized ''Stargate Universe'' which the network had approved to have a bigger budget, be less mythology-dependent, and have more focus on character development; ''Stargate Universe'' premiered on October 2, 2009, and was cancelled after two seasons. Merchandise for ''Stargate Atlantis'' includes games and toys, print media, and an original audio series. With the cancellation of ''Stargate Universe'', the intended direct to-DVD ''Stargate Atlantis'' movie, entitled ''Stargate: Extinction'', was also cancelled.
''Stargate Atlantis'' follows the present-day adventures of Lt. Colonel John Sheppard and his military team from Earth that, along with two dozen other teams, explore distant planets in the Pegasus Galaxy. They use an alien device known as a Stargate that was built millions of years ago by an advanced race of humans known as the Ancients. The expedition is based in the Lost City of Atlantis on the planet "Lantea". The city was built millions of years ago and abandoned 10,000 years ago by the Ancients. Five to ten million years ago, due to a plague in the Milky Way Galaxy, they were forced to flee to the Pegasus Galaxy, and there they seeded life on hundreds of worlds as they had done to Earth in the Milky Way. After encountering a powerful enemy known as the Wraith and going to war with them for one hundred years, the Ancients ultimately lost and were forced to submerge their city beneath Lantea's ocean, which, in the Stargate universe, is the source of the Greek myth of the Lost City of Atlantis.
''Stargate: Atlantis'' episodes feature a self-contained story that also contributes to the larger storyline of the war against the Wraith and the Atlantis residents' search for the means to destroy their enemy. Each season has also featured a two-part episode, and some episodes that, while not technically two-parters, feature direct continuity with the story of the previous episode (for example, season 3 "Progeny" and "The Real World"). Each episode begins with a cold open, sometimes preceded by a recap of events relevant to the upcoming narrative. The opening credits feature an original theme by Joel Goldsmith. Though they were drastically cut at the start of season 2, the full credits were recovered after the mid-season two-parter. They were again cut short in the 5th season.
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