Four decades after opening—and transforming Orlando —the Magic Kingdom is still the No. 1 most popular theme park, working its pixie-dust charm on more than 17 million annual visitors.Yet Mickey Mouse has some recent competition: the rising star of the theme-park industry is an English boy with round spectacles and a scar on his forehead.The $265 million Wizarding World of Harry Potter, which opened in the summer of 2010, single-handedly carried Islands of Adventure into the world's top 10 most-visited theme parks, delivering a 29 percent jump in attendance. “That's just huge growth when you're talking about the top of the rankings,” says Robert Niles, editor of Theme Park Insider The takeaway? If you build it, they will come—especially if you spend a boatload of money and create an experience that's, to use the industry's favorite buzzword, immersive. The latest and greatest new theme-park attractions are designed to pull us right into the story, whether we're engaging in an epic robot battle, soaking up the retro cars culture along Route 66, or downing pints of butterbeer with Hogwarts students.One big, exciting new attraction can get folks through the turnstiles, says Niles. “And if you look at the really huge news happening this year—it's Cars Land at Disney California Adventure, Transformers at Universal Studios Hollywood, the new Manta roller coaster at SeaWorld San Diego,” he says. “I think 2012 will be southern California's year.”But if you're looking for even bigger growth, look even farther afield to Asia, which passed the 100-million-visitor milestone for the first time in 2011. Hong Kong 's Ocean Park, No. 11, got a boost from a new rainforest adventure and aquarium-themed zone, while Nagashima Spa Land challenges visitors to brave the world's longest roller coaster, Steel Dragon 2000 . With a number of major new parks planned for the world's most populous continent, Asia's slice of the theme park pie should only get bigger.Even some traditional theme parks are getting spruced up: for its 60th anniversary in 2012, the De Efteling park south of Amsterdam has unveiled Aquanura, a fountains-and-light extravaganza.Get the scoop on which other attractions and events are drawing crowds to the world’s most-visited theme parks, based on Themed Entertainment Association 's latest attendance report (2011).