It’s official: 1 World Trade Center is now New York's tallest skyscraper

A steel beam labeled "1271 ft" was secured to One World Trade Center on Monday, making it the tallest building in the city — and demoting the Empire State Building to No. 2.

Applause broke out as the unfinished Ground Zero tower became the king of the New York skyline, eclipsing King Kong's perch.

The so-called Freedom Tower will eventually be 1,776 feet.

The Empire State Building is 1,250 feet high, not counting its antenna.

The tallest skycraper in the world when it was built in 1931, the Midtown landmark fell to second place when the North Tower of the World Trade Center was erected in 1972.

After the 9/11 attacks, the Empire State Building regained its title of tallest in the city.

Once finished, One World Trade Center will have 104 floors, including 71 office floors with 3 million square feet of space.

"It's nice for it to back up again," said Joeph Lashendock, 49, an iron worker who has been toiling on the World Trade Center site for almost three years.

"It's impressive but I still prefer the twin towers," said Alan Taylor, 68, a tourist from the United Kingdom who visits every year.

Assembly Speaker Sheldon Silver (D-Manhattan) said the new tower "serves as a beacon signaling our courage, our determination and our incredible resilience."

blesser@nydailynews.com