"It's bittersweet": Rebuilding the World Trade Center
1 May 2012 Last updated at 01:03 BST
After years of delays and a major redesign, One World Trade Center has reclaimed the title of tallest building in New York City.
The BBC's Laura Trevelyan talked to several New Yorkers on the day 1 WTC reclaimed the record previously held by the Twin Towers, destroyed in the 9/11 attacks, with a single steel beam fitted into place.
"It's bittersweet," one construction worker said. "It's a beautiful thing we're up there, but it's a terrible reason we have to put it up."