The World Trade Center’s newest, $2.5bn skyscraper reached its full 80 stories Thursday – one of three high-rises now up at the site, with one more to go.

Almost 15 years after the twin towers collapsed, the site of the September 11 terrorist attacks has turned into a resplendent hub of soaring architecture, bustling businesses and urban greenery.

But a series of construction security fences signal that there’s still plenty of unfinished work before the 16-acre site is totally back to life.

A ceremony on Thursday marked the topping out of 3 World Trade Center, with about 1,000 workers signing a massive construction bucket that was lifted to the brim, along with a big American flag. It was a victory for the tower that had languished for a few years before financing finally came through.

Several workers at the ceremony still remembered the 16-acre pit of fiery debris they helped to clean up after the 9/11 attacks.

“This is very emotional,” said 53-year-old Frank Hussey, a native of Jamaica who watched the original towers fall in 2001 and has worked on every skyscraper that is now up at the site. “To have witnessed what happened and to go through all the different phases of cleaning up and construction, and watch people’s spirits go from low to high – all that makes today a great day.”

The building at 3 World Trade is one of three new skyscrapers that replace the twin towers destroyed almost 15 years ago. The others are the 72-story 4 World Trade Center and the main edifice of the rebuilt site, the 104-floor One World Trade Center that dominates the post-9/11 Manhattan skyline and is the city’s tallest building.

A fourth planned skyscraper is 2 World Trade Center, the foundation of which was built up to street level several years ago. That’s where the money also stopped, due to the lack of an anchor tenant that would make financing more likely.

Developer Larry Silverstein, who is responsible for erecting the third and fourth towers, told the Associated Press he is confident he will find an anchor tenant, noting “failure was not an option”.

Workers guide a boom pouring concrete on top of 3 World Trade Center in New York. Behind them is One World Trade Center. Photograph: Mark Lennihan/AP



As for the rest of the 16-acre site, there is the shimmering new transportation hub, with huge, white “wings” that Spanish architect Santiago Calatrava says represent the souls of the nearly 3,000 people who died in the 9/11 attacks.

The all-white marble underground concourse that crosses the entire trade center site is filled with shops that will also open in August.

Blocked off by chain-link security fences and armed guards is a bulky new dark gray building at the site’s south-west corner, with vehicle ramps leading underground. This is the security center that will screen trucks loaded with deliveries. The hard-core, concrete and steel construction of the complex is softened by the grass and trees surrounding the two memorial pools built in the footprints of the twin towers.

And in the works on the roof of the security center overlooking the memorial is the elevated public Liberty Park, nearing completion with a Living Wall installation of periwinkle, Japanese spurge and Baltic ivy.