David W. Dunlap

NEW YORK: If the winds are forgiving enough over Lower Manhattan — up where workers can see the whole outline of the island’s tip — a steel column will be hoisted into place today atop the exoskeleton of 1 World Trade Center and New York will have a new tallest building.

Poking into the sky, the first column of the 100th floor of 1 World Trade Center will bring the tower to a height of 1,271 feet, making it 21 feet higher than the Empire State Building.

After several notorious false starts, a skyscraper has finally taken form at ground zero. At first, only its twin cranes could be detected creeping over the jumbled tops of nearby towers. Then, at the rate of a new floor every week, it began reshaping the Manhattan skyline as seen from New Jersey.

From a construction point of view, the completion of the framework, known as the topping out, will be a more significant milestone. That is to occur in a couple of months, when 1 World Trade Center reaches 1,368 feet at its rooftop parapet, identical in height to the first 1 World Trade Center, which was destroyed, with the rest of the complex, in the Sept. 11 terrorist attacks.

The ultimate topping out will be the completion next year of an antenna that will bring the structure’s overall height to 1,776 feet.

Unlike its predecessor, the new 1 World Trade Center is not the tallest building in the world. The Burj Khalifa in Dubai holds that title.

It is not even the tallest in the United States. That would be the Willis Tower in Chicago, once known as the Sears Tower.

But its importance to the landscape will set it apart.

“It’s the marker for the memorial,” said David M. Childs, the architect who led the design team at Skidmore, Owings & Merrill, where he is a consulting partner.

“If you’re coming in from Newark Airport, this is the one you’ll look to. Somebody will say: ‘You see that tall building? That’s ground zero.’?”