Who watches the Watchmen? As it turns out, lots of people.

Zack Snyder’s graphic novel adaptation dominated the box office this weekend with an estimated $55.7 million, making it the biggest opening for 2009 thus far. But that’s about the only record the movie’s broken, failing to meet the media’s expectations that it would beat Snyder’s other box office behemoth, 2006’s 300, which still reigns as March’s biggest opening movie ever (with $70.9 million) and the biggest opening for an R-rated film. Watchmen’s opening ranks in the 12th spot for a comic book adaptation and the sixth for biggest R-rated opening.

Though Watchmen was the only movie in wide release this weekend, none of the other films on the chart bothered to put up much of a fight, with none coming anywhere close to registering double digit numbers. Jonas Brother: The 3D Concert Experience, in fact, seemed to be hit the hardest, having the biggest second-week drop of the year with a 78 percent fall to ninth place, bringing in an abysmal $2.7 million.

In second place for the weekend was Tyler Perry’s Madea Goes to Jail, with $8.8 million, bringing its three-week total gross to $76.5 million. Taken stayed strong in third with $7.4 million while Slumdog Millionaire continued its winning streak with $6.9 million, topping out its 17-week total at $125.4 million. Finally, Paul Blart: Mall Cop, continues to defy all odds and expectations, climbing back into the top five with $4.2 million and a total gross of $133.6 million.

Next week Dwayne “The Rock” Johnson continues his transformation from badass action hero to family-friendly leading man with Race to Witch Mountain (also starring Carla Gugino and AnnaSophia Robb). Also competing for the top spot will be The Last House on the Left, a remake of the 1972 Wes Craven classic; Miss March, The Whitest Kids U Know’s Trevor Moore and Zach Cregger’s first foray to the big screen; and Sunshine Cleaning, with Amy Adams and Emily Blunt, in limited release.