DOWNTOWN MIAMI Plans for world's tallest condo tower unveiled Miami's new landmark? A developer is proposing to build the world's tallest condo tower -- 1,200 feet and 110 stories high -- on Biscayne Boulevard. BY MATTHEW HAGGMAN firstname.lastname@example.org The South Florida building boom may be reaching new heights, with a developer proposing what could be the world's tallest condominium in downtown Miami. Leon Cohen is preparing to submit plans with the city of Miami to build a condo tower and apartment-hotel tower that would each rise 1,200 feet along Biscayne Boulevard. If built, both 110-story skyscrapers would be the tallest in Florida, and the condo tower would rank as the tallest residential high-rise in the world, Cohen said. The 21st Century Tower in Dubai, 883 feet tall, is currently the world's tallest residential building, according to Germany-based Emporis, which tracks high-rise construction. Florida's tallest high-rise is the 789-foot Four Seasons Hotel & Tower on Brickell Avenue in Miami. But Cohen, who grew up in Paris and moved to Miami Beach in 2000, faces severe hurdles in getting approvals to build so high. The Federal Aviation Administration has limited the height of new buildings along Biscayne Boulevard so as not to interfere with planes flying into Miami International Airport. Called Empire World Towers, Cohen's development would rise on an L-shaped, roughly two-acre parcel at 330 Biscayne Blvd. The two towers, projected to include 1,000 condo units and 500 apartment-hotel units, would wrap around the Holiday Inn hotel at the corner of Biscayne Boulevard and Northeast Fourth Street. MIAMI = NEW YORK ''Miami is what New York was in 1945,'' Cohen said Wednesday, who shrugged off any concerns about too many new condos being built in downtown Miami. ``Biscayne Boulevard will become Fifth Avenue.'' On Monday, the developer formally purchased the property from Allen Greenwald for $31.7 million, he said. Demonstrating how Miami's prices have raced upward amid the region's ongoing condo boom, Greenwald purchased the site in April 2004 for $16.5 million. Edie Laquer of Laquer Corporate Realty in Miami, who called the project ''innovative,'' brokered the sale. AIR NAVIGATION FAA public affairs manager Kathleen Bergen, who works out of the agency's Southeast region office in Atlanta, said the heights of all buildings are considered on a case-by-case basis. FAA staffers perform a computer analysis studying the longitude and latitude of a structure to determine if a building is a hazard to air navigation. It is not uncommon, she said, to negotiate with developers over height, markings and lighting. ''Miami is a very busy place for us for airspace studies,'' Bergen said. ``That is much taller than what has been proposed. But we would take a look at any proposal that came in.'' Developer Pedro Martin, who plans to build high-rise condo towers nearby at 600 and 900 Biscayne Blvd., said his building heights were limited to 649 feet. ''Would they go to 1,200? I have no idea,'' Martin said, who added that projects like Cohen's, which are located closer to downtown Miami, may be allowed to rise higher. Cohen insists he can win approvals for the two towering structures -- and expressed total confidence he can build at least 900 feet high. ''I would not be talking about this if I didn't think we could do it,'' he said. Cohen, whose company is Maclee Development, said this would be his biggest project. He completed a partially built, 52-story hotel in New York, the Flatotel Building. He's now constructing a six-story condo hotel, the Empire Ocean Residence, at the site of the former Charles Hotel at 1475 Collins Ave. in South Beach. The developer hired Alexandria, Va.-based Aviation Management Associates to conduct a study on the project. In the report, Aviation Management concluded Empire World Towers would create some problems for aviation but that those issues could be solved. BUILDING CHALLENGES Meanwhile, the building creates significant engineering challenges. Cohen, for instance, said the building will be the tallest concrete structure in the world. ``This is due to the hurricane weather in South Florida.'' Still, some are skeptical. ''Why so high?'' said real estate analyst Michael Cannon, who also questioned if condo buyers would want to live so high. ``I hope they do a good wind test because you have some major atmospheric pressure on a building that high.''