FACTBOX: Comic book movies at the box office

(Reuters) - "Watchmen," which opens in North America on Friday through Time Warner Inc's Warner Bros. Pictures, is the latest in a long line of superhero movies to hit the big screen.

Last year's Batman sequel "The Dark Knight" was the biggest movie since "Titanic." But comic-book adaptations are not guaranteed successes, as shown last December by "The Spirit" from comic book creator-turned-filmmaker Frank Miller.

The 1978 blockbuster "Superman" proved to Hollywood that comic-book movies could be hits, while 1997's much-maligned "Batman & Robin" did to the Caped Crusader what the Joker could not.

Following the 2000 release of "X-Men," superhero movies regained their footing. Here are some key adaptations along with their worldwide ticket sales.

-- "The Spirit" (2008), $37.7 million.

-- "The Dark Knight" (2008), $1 billion.

-- "Iron Man" (2008), $582 million.

-- "Fantastic Four: Rise of the Silver Surfer" (2007), $289 million.

-- "Spider-Man 3" (2007), $890.9 million.

-- "Superman Returns" (2006), $391.1 million.

-- "Fantastic Four" (2005), $330.6 million.

-- "Elektra" (2005), $56.7 million.

-- "Spider-Man" (2002), $821.7 million.

-- "X-Men" (2000), $296.3 million.

-- "Batman & Robin" (1997), $238.2 million

-- "Howard the Duck" (1986), $38 million.