NEW YORK (CBSNewYork) — As New York City prepares to mark the 14th anniversary of 9/11, construction continues at the World Trade Center site.

But as CBS2’s Dick Brennan reported, while rebuilding has been a slow process, there has also been great progress.

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The skyline where the World Trade Center once stood is now standing tall again in a whole new way, and the work is not done yet.

Developer Larry Silverstein said the World Trade Center site is coming back one building at a time.

“You have the office towers, you have One, Two, Three, Four and Seven, and now the PATH terminal,” Silverstein said.

Silverstein had received the lease to the World Trade Center site only six weeks before the 2001 terror attacks. And almost immediately upon taking over, he had to rebuild.

The World Trade Center is 16 acres wide, anchored by One World Trade Center. Tower three is set to be completed by 2018 and the entire site should be finished by 2020.

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“The last piece of the puzzle is falling into place now, and that’s with respect to Two World Trade Center,” said Silverstein.

In building seven, Silverstein’s team of architects are working on the future of building two. Silverstein is concluding a deal with 21st Century Fox to be an anchor tenant there, Brennan reported.

The building’s completion will culminate an extremely difficult Ground Zero rebuilding process that has taken so many years, in part, because of what happened there, Brennan reported.

“Almost 3,000 people lost their lives here on 9/11. You have to deal with that with tremendous sensitivity,” said Silverstein.

Silverstein, who is 84 years old, said sometimes he wondered if it would all come together in his lifetime, but he still looks forward to continuing the challenge by keeping positive.

“(Brennan: Have any regrets?) You can always look back and think of things that might have been different,” Silverstein said. “Don’t look back, look forward. The glass is always better half full than half empty, and look at life in a positive way.”

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Fourteen years later, the rebuilding goes on.