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A new design for the Freedom Tower (search) at the World Trade Center site slopes gracefully into a spire rising 1,776 feet, echoing the Statue of Liberty, images released Friday show.

The new plan -- which comes after months of contentious negotiations between designers Daniel Libeskind (search) and David Childs (search) -- retains many elements of Libeskind's original plan but appears to smooth out its most angular elements.

At a news conference to unveil the design, Childs said the tower must be "simple and pure in its form, a memorable form that will reclaim the resilience and the spirit of our democracy."

Mayor Michael Bloomberg (search) said the tower -- which planners said would be the world's tallest -- would "dramatically reclaim a part of the New York City skyline that was lost on 9/11."

"This is a wonderful day, not just for New York, but for America," said Bloomberg, who appeared with the architects and Gov. George Pataki to unveil the new design.

The cost is estimated at $1.5 billion, said Charles Gargano, vice chairman of the Port Authority of New York and New Jersey (search), the public agency that owns the site.

Gargano said the Port Authority, which had headquarters in the World Trade Center, plans to occupy one-third of the building's office space. The governor's Manhattan offices will also be located in the tower.

The plan follows the original, asymmetrical structure proposed by Libeskind, who was originally tapped as the architect to remake ground zero by the Lower Manhattan Development Corp. (search), the agency charged with redevelopment.

But Childs, who was appointed by leaseholder Larry Silverstein (search), succeeded in including a lattice structure filled with energy-generating windmills at the top of the building. Childs likened the suspension elements of the new design to the Brooklyn Bridge, with the bottom of the building "torqued or twisted."

The building is to be put up on the northwest part off the World Trade Center site, not on the footprint of the vanished towers.

The plan calls for a cable suspension structure that creates an open area above the building's 70 floors of office space, and houses windmills to generate energy. The windmills could provide 20 percent of the building's energy.

Silverstein, often a silent presence at redevelopment announcements, said he was emotionally moved by both the design and the process of creating it.

"What we see today is, in my judgment, beautiful. It's spectacular; it is also very practical," Silverstein said.

He has promised to build one new skyscraper at the site each year after the expected completion of the Freedom Tower in 2009, finishing the five-building complex in 2013.

Taiwan's Taipei 101 tower, 1,676 feet tall, recently supplanted Malaysia's 1,483-foot Petronas Twin Towers as the tallest building in the world when crews completed installing the pinnacle. The 110-story World Trade Center towers were 1,350 feet tall.

Despite persistent reports of conflict between the two designers, Childs told NBC's "Today" show they had "a spectacular time working together. ... Creative minds have different thoughts about how you do things. I wouldn't want to work with somebody who would just say yes."

Added Pataki: "This represents a melding of two very, very talented, creative geniuses."

Negotiations had been contentious between the two architects. Libeskind, who created the Jewish Museum in Berlin but has little experience with major commercial projects, once compared the relationship with Childs, who designed the new Time Warner building in Manhattan, to a "forced marriage."

Several safety features were included in the design, such as separate staircases for firefighters and "blast-resistant glaze" on the lobby glass.

Richard Meier (search), an architect who was a finalist for the trade center design competition won by Libeskind, questioned the timetable set by the governor, who wants construction on the tower to begin next summer before the national Republican convention begins.

"We're not just talking about a building here; we're talking about a large area of the city that's being developed and there's a relationship between this new building and everything else that's going on," Meier said. "If the rest of this site is developed this way, it's going to be chaotic."