<P> When completed in 1972 , 1 World Trade Center became the tallest building in the world for two years , surpassing the Empire State Building after a 40 - year reign . The North Tower stood 1,368 feet ( 417 m ) tall and featured a telecommunications antenna or mast that was added at the top of the roof in 1978 and stood 362 feet ( 110 m ) tall . With the 362 - foot ( 110 m ) - tall antenna / mast , the highest point of the North Tower reached 1,730 feet ( 530 m ) . Chicago 's Sears Tower , finished in May 1973 , reached 1,450 feet ( 440 m ) at the rooftop . Throughout their existence , the WTC towers had more floors ( at 110 ) than any other building . This number was not surpassed until the advent of the Burj Khalifa , which opened in 2010 . Each tower had a total mass of around 500,000 tons . </P>
<P> When completed in 1972 , 1 World Trade Center became the tallest building in the world for two years , surpassing the Empire State Building after a 40 - year reign . The North Tower stood 1,368 feet ( 417 m ) tall and featured a telecommunications antenna or mast that was added at the top of the roof in 1978 and stood 362 feet ( 110 m ) tall . With the 362 - foot ( 110 m ) - tall antenna / mast , the highest point of the North Tower reached 1,730 feet ( 530 m ) . Chicago 's Sears Tower , finished in May 1973 , reached 1,450 feet ( 440 m ) at the rooftop . Throughout their existence , the WTC towers had more floors ( at 110 ) than any other building . This number was not surpassed until the advent of the Burj Khalifa , which opened in 2010 . Each tower had a total mass of around 500,000 tons . </P>
how tall were the twin towers in floors
how tall were the twin towers in floors
110
110