The gleaming World Trade Center rising from Ground Zero in New York will be far more sophisticated and impressive than the destroyed Twin Towers it replaces, project leaders vowed Thursday.\"When the buildings are built, we will look back at them and say these are a vast improvement on what was there originally,\" World Trade Center developer Larry Silverstein told journalists in an office overlooking the ant hill-like activity at the construction site. After years of delays, the principal building, Tower One, is now stunning, with 76 of the eventual 104 floors built, and that number expected to enter the 80s before the upcoming 10th anniversary of the September 11, 2001 terrorist attacks. Sleek and awe-inspiring, the Twin Towers used to lord over the Manhattan skyline and their collapse upon being hit by hijacked airliners was part of a national trauma that even went beyond mourning for the nearly 3,000 people killed. The four-tower complex finally taking shape will look entirely different. When finished, Tower One will rise to 1,776 feet (540 meters), higher than the Twin Towers and referencing the 1776 date of America\'s declaration of independence from Britain. Gradually stepping down from the tallest building in the Big Apple will be the 78-story Tower Two designed by Britain\'s Norman Foster, then towers three and four.But where the architectural spirit of the old towers was plain to the point of brutal, the new World Trade Center emphasizes environmentally friendly architecture, retail space, transport links, and unprecedented security.The head of the Port Authority of New York and New Jersey, which owns the site, said the goal is to fit comfortably into an increasingly residential and lively lower Manhattan, not to make a point about American power.\"We had to restore what makes New York City,\" Port Authority Director Chris Ward said. \"Soaring, beautiful office buildings is what New York needs... It didn\'t need at this point a symbol, a message.\"The new World Trade Center, he said, \"is not a symbol, it\'s a site.\"Balancing that cool-headed approach is a memorial to the dead that will open for the 9/11 anniversary ceremonies to be attended by President Barack Obama and George W. Bush, who was in the White House at the time of the atrocities. The memorial consists of two fountains in granite-lined pits occupying the exact locations of the foundations of the fallen Twin Towers.During a test run on one fountain, water cascaded from the rim into the huge square pit, disappearing down a smaller, dark square in the center. The names of all the dead from that day are etched in bronze around the edges, though covered, for now, with heavy protective materials.Simple, yet evocative, and surrounded by a grove of small oak trees, the memorial is sure to immediately become one of the country\'s most famous, moving monuments. A museum is being constructed underneath.Watching workers put final touches, architect Michael Arad told visiting journalists that the intention was \"the equivalent of building a moment of silence.\" The pits and the ceaseless water represent memory and sorrow -- \"this notion of these empty vessels, that water flows into them but they cannot be filled.\"Yet the miniature urban forest around them and the generous open space will echo what Arad said was the life-affirming role of nearby public squares in New York, where crowds would gather in the days after 9/11.\"People might come here alone,\" he said. \"But they won\'t be alone.\" Silverstein said the whole World Trade Center -- one of the biggest and most complex building projects anywhere -- would be finished by 2016.The project has been widely criticized as slow and shambolic, leaving the vast hole of Ground Zero to scar the heart of lower Manhattan for years.Silverstein is a larger-than-life figure and veteran developer, who had the extraordinarily bad luck to buy the World Trade Center lease six weeks before the Al-Qaeda hijackers struck. He acknowledged that time was lost afterwards in legal disputes and financial wrangling, including in his battle to secure billions of dollars in insurance money. But he said a neighborhood left a \"wasteland\" by fleeing businesses and the horrific physical spectacle of Ground Zero was now the site of \"enormous progress and exciting as hell.\" \"I don\'t know of any place in America where something more spectacular has gone forward,\" Silverstein said.