WINTER HAVEN, Fla. - Legoland officials said Wednesday they are counting on the popularity of the little plastic building blocks to draw families to their newest theme park, which will open this fall near Orlando.

Incorporating as many as 50 million of the iconic Lego bricks in rides and attractions geared toward children 2 to 12, Legoland Florida is under construction in sleepy Winter Haven, a 45-minute drive south of Walt Disney World and the other main Orlando parks. The opening is planned for October, but a firm date has not been set.

It will be the largest of five Legolands in the world and the only one on the U.S. East Coast, with others in California, England, Germany and Denmark, where the toy company was founded.

The 150-acre park is being built on the former site of Cypress Gardens, one of Florida's earliest theme parks. Cypress Gardens opened in the 1930s but closed in 2009, unable to compete with attractions clustered closer to Orlando. Legoland is retaining the old park's gardens and famous water ski shows, and eventually will add its water park to the mix. Also left over from Cypress Gardens is the Flying Island, which raises riders 175 feet in the air for a bird's eye view of the grounds.

"I think Legoland has its place in the theme-park community," park general manager Adrian Jones said Wednesday, looking out over a vast construction site where roller coaster tracks hint at what will eventually take shape there. "We focus primarily and always on families with children aged 2 to 12. And we're good at that. We don't try to be all things to all people."

Besides four gentle roller coasters and other family rides, visitors will get to see Legoland's trademark models crafted from Lego bricks, including miniature skylines of famous cities, a castle and jungle animals, with exhibits ranging in size from intricate to life-size to larger-than-life. Of course, there will be plenty of places where kids to get their hands on Legos and build things for themselves.

"We have three or four key areas where we can expand and build rides as the park grows," Jones said.

Jill Swidler, the park's marketing manager, said the focus for the first 18 months or so will be drawing visitors who live within a two-hour radius, including the Orlando and Tampa areas. Then they'll make a bigger a push to divert families away Walt Disney World and the other Orlando attractions for a day trip. She said the Lego brand name will distinguish it from Cypress Gardens, which besides having grown outdated was hurt by its distance from the other attractions.

"I think the difference is, we have the power of the international brand," she said. "Everyone knows Lego. People have Legos in their cars, in their basements, their kids' rooms, and it's really that familiarity with the brand that is going to get people to drive the 45 minutes from Orlando and Tampa. It's really not that far."

Legoland Florida also has behind it the might of Merlin Entertainment Group, the largest operator of attractions in the United Kingdom, whose holdings include the Madame Tussauds wax museums and the London Eye observation wheel. Merlin also has on the drawing board an Orlando Eye observation wheel that will anchor a new shopping and entertainment complex in the central Florida attractions corridor.

Inspired by the Lego bricks first named by a Danish toy maker in 1932, the first Legoland opened in Dillund, Denmark, in 1968. Parks in Windsor, England, outside London, and in Carlsbad, Calif., went up in the 1990s, and a Legoland opened in Gunzburg, Germany, in 2002.

A single-day ticket to Legoland Florida is being offered now for $65 plus tax for adults and $55 plus tax for children 3-12 and seniors. Kids 2 and under get in free. After the opening, admission will go up $10 per ticket. Annual passes start at $99.