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.