LOS ANGELES, May 23 (Xinhua) -- All six "Star Wars" films were being screened together in the United States for the first time Wednesday at a fan convention here on the eve of the 30th anniversary of the original film's release.

The screening began in the morning at the Los Angeles Convention Center "Star Wars: Episode I -- The Phantom Menace," followed by the other two films of the second trilogy, then by the three films of the first trilogy. Intermissions were scheduled every two-to-three hours between films.

The screening is expected to take 17 hours and end at 2 a.m. Thursday, organizers said.

The five-day "Star Wars" Celebration IV begins Thursday, with the opening day open only to fan club members and the remaining four days open to the public.

Mayor Antonio Villaraigosa will declare Friday, the 30th anniversary of the release of the first "Star Wars" film, as "Star Wars" day in Los Angeles and U.S. Postal Service officials will unveil the "Star Wars" stamp, convention organizers said.

Created by Hollywood director-producer George Lucas, the "Star Wars" series films have become a worldwide pop culture phenomenon and one of the most successful franchises of all time, generating an estimated 20 billion dollars from box office and related merchandise sales in last 30 years.