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Freedom Tower spire arrives in New York City

Chris Pedota / Pool via Getty Images

Parts of the spire for the Freedom Tower make their way on a barge to lower Manhattan on Dec. 11 in New York City.

By NBC News and news services

Chris Pedota / Pool via Getty Images

The barge is carrying nine pieces of steel that will eventually top off One World Trade Center at a symbolic 1,776 feet, becoming the tallest building in the Western Hemisphere.

The pieces that make up the giant spire that will sit atop the World Trade Center's tallest building arrived in New York City on Tuesday.

A barge carried nine pieces of the 408-foot steel spire across New York Harbor from New Jersey's Port Newark.

Meanwhile, workers on the 104-story skyscraper were busy pouring concrete that will hold the spire.

One World Trade Center rises, providing breathtaking views of Manhattan

The trade center's director of construction, Steven Plate, said the spire marks a post-9/11 milestone that signifies New York City is "better than ever."

The heaviest piece weighs nearly 70 tons.

SPI, dbox via Getty Images

An artist's rendering shows the lower Manhattan skyline as proposed after the construction of the future Freedom Tower, left, and other buildings.

The spire is expected to rise into the Manhattan sky by spring.

Plate says the 1,776-foot high-rise — symbolizing America's freedom — will be the tallest building in the Western Hemisphere.

View a panoramic image of the National Sept. 11 Memorial

The high-rise is one of five new skyscrapers planned for the new World Trade Center. The project will also include a 9/11 memorial and museum, a transportation hub, 550,000 square feet of retail space and a performing arts center.

The twin towers of the old World Trade Center collapsed after hijackers flew airplanes into them on Sept. 11, 2001.

The Associated Press contributed to this story.

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Six years since construction began on 1 World Trade Center, the tower will soon surpass the height of the Empire State Building's roof. The iron workers placing and setting each beam in the shadow of the 9/11 attacks say they are building out of a "sense of necessity" and know that the tower, now soaring nearly 1300 feet, will help the nation and the iron workers themselves heal. Many of the workers building the tower helped clean the smoldering debris in the days after the terrorist attack. Harry Smith reports.