By Barbara Liston

WINTER HAVEN, Fla (Reuters) - A symbolic 50 millionth Lego brick was snapped in place on Friday on a giant red octopus at Legoland Florida, a new theme park opening to the public this weekend southwest of Orlando.

The park is located on the site of one of Florida's original tourist attractions, the 75-year-old Cypress Gardens, and is about an hour's drive from Walt Disney World's Magic Kingdom, the theme park with the world's highest attendance.

The new park, the fifth and largest Legoland in the world, targets families with children ages 2 to 12, and it seemed to be a hit among the Lego fans and Florida schoolchildren invited to check out the attraction ahead of Saturday's opening.

A big draw was Miniland USA, where national landmarks and Florida cities have been recreated out of 30 million Lego bricks, according to master builder Jason Miller.

A Lego version of the Empire State Building stands at more than 20 feet high in Miniland USA, and the Golden Gate Bridge spans 22 feet.

"That is crazy," said 12-year-old Anthony Martinez, a dedicated Lego builder from Miami, as he admired the New York cityscape. "It takes some serious talent to build those kind of things. I would love to know how they do this."

Kurstin Greene, a 9-year-old from Winter Haven who likes to build houses out of her personal stash of Legos, said she couldn't attempt something of the scale of the miniature Lego U.S. Capitol.

"We don't have enough Legos for that," Greene said.

Miller said the two biggest construction projects at Legoland Florida were a brontosaurus near the park's entrance and a bust of Albert Einstein in the hands-on Imagination Zone, each of which required six to seven builders working for four months to complete.

Norvell Holveck, 66 and a grandfather from San Angelo, Texas, said he expects Legoland to attract his generation as well.

"It's really a neat deal. You could spend days right here (in Miniland) and not see everything," Holveck said.

Legoland has restored what it calls "the soul of the park" -- the historic Cypress Gardens with its collection of native plants such as azaleas and camellias, and the sprawling 72-year-old Banyan tree planted as a seedling in a five-gallon bucket in 1939.

The park also features several rides, including a wooden roller coaster. The once-famous ski shows where swimmer and actress Esther Williams filmed some of her water-themed shows in the 1950s and '60s are being resurrected with Lego people manning the skis.

The company announced on Friday that it will re-open a water park on the property in 2012 and develop a resort hotel, likely in 2014.

Nick Varney, chief executive officer for Merlin Entertainments Group, told Reuters the central Florida tourist destination was an obvious market for his company to build its latest Legoland.

And locating the theme park in Winter Haven instead of Orlando was a calculated financial move, Varney said.

Varney said Merlin bought the property for $25 million in January 2010 after a previous owner had recently invested $100 million in upgrades.

By acquiring an existing theme park property, Varney said the company saved on infrastructure and government permits and was able to open years faster than a theme park built from the ground up.

As a comparison, Varney said the company is building a similar theme park from scratch in Malaysia. Scheduled to open in 2012, it has an expected price tag of $300 million.

(Editing by Colleen Jenkins and Jerry Norton)