New construction at the site is scheduled to begin next year.
United Flight 93 was traveling from Newark, N.J., to San Francisco when it was hijacked by four terrorists in 2001.
The 9/11 Commission says terrorists likely aimed to crash the plane into the White House or the U.S. Capitol, but passngers fought back and the jet went down in a field near Shanksville, Pa.
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At the new multi billion-dollar World Trade Center, two towers are nearing completion and once again dominate the lower Manhattan skyline, according to an Associated Press report.
Developers of the project say:
— Most of the 8-acre memorial quadrangle at the World Trade Center opened last year on the 10th anniversary of the attacks. Since then, some 4.5 million people have visited the memorial, with its twin reflecting pools where the towers stood. But a museum being built in a cavern beneath the plaza is still incomplete. Work all but stopped last fall because of a funding dispute between the memorial foundation and the Port Authority of New York and New Jersey. Joseph Daniels, president of the National Sept. 11 Memorial and Museum, said that once construction resumes it will take more than a year to finish the job, meaning the museum might not open until 2014.
— One World Trade Center, formerly known as the Freedom Tower, will open in 2014 on the northwest corner of the trade center site with 3 million square feet of office space. Tenants so far include magazine publisher Conde Nast and the federal government's General Services Administration. The spire atop the 104-story building will reach the symbolic height of 1,776 feet. There will be observation decks on the 100th, 101st and 102nd floors. The building without the spire has reached its full height of 1,368 feet. It is expected to cost $3.9 billion by the time it is finished.