he Freedom Tower in New York is the tallest building in the United States at 542 metres, surpassing Chicago's Willis Tower

The New York edifice, whose official name is One World Trade Center, takes the title as tallest after including the spire installed this year, which raises it from 417 metres to 542 metres, leaving the 442-metre Chicago skyscraper behind.

Once complete, the Freedom Tower will be the third tallest building in the world, trailing only the Burj Khalifa in Dubai and the Makkah Royal Clock Tower in Mecca, Saudi Arabia, the CTBUH said.

“The design of One World Trade Center, as explained to us, reinforces its role as a symbol of resurgence on this important site,” CTBUH Executive Director Antony Wood said.

The building stands on the site of the original Twin Towers of the World Trade Center, destroyed in the terrorist attack of September 11, 2001.

Chicago’s Willis Tower, formerly the Sears Tower, stands 130 stories high and is topped by an observation deck with a popular bar and restaurant.

For many years New York retained the title for the tallest skyscraper in the world, thanks to the Empire State Building, but in 1974 the Sears Tower went up in Chicago and snatched that honour away.