The premiere of the film version of the landmark graphic novel "Watchmen" sent ticket- buying fans to movie theaters in droves over the weekend, powering the dark superhero allegory to the top of the box office, for the week ending March 8. The film earned an estimated $55.7 million and became the sixth highest-grossing R-rated film debut ever, according to estimates from box office tracking firm Nielsen EDI and other industry sources.

Directed by Zack Snyder, "Watchmen" is set in an alternate history mid-1980s U.S., which buckling under the threat of a nuclear attack by the Soviet Union and where superheroes are part of everyday life. The film is based on the Alan Moore/Dave Gibbons novel of the same name and is known for its excessive violence and dark themes.

Tyler Perry's "Madea Goes to Jail" dropped to second place after two weeks at the top, taking in $8.8 million. The comedy has done $76.5 million in three weeks. The Liam Neeson action thriller "Taken" continues to chug along, taking third place with $7.5 million and lifting its total to $118 million.

"Slumdog Millionaire," the best-picture Oscar winner, was fourth with $6.9 million, bringing its total to $125.4 million. "Paul Blart: Mall Cop" rounded out the top five with $4.2 million. It has done about $134 million since its release two months ago.

Final figures are due Monday.