Even though they were ultimately built to 110 stories each, the Twin Towers were originally planned to have 80 to 90 floors. The Port Authority public relations staff recommended the change to make them the world's tallest buildings.
One World Trade Center, known colloquially as Freedom Tower, was built on the site of the original towers. Construction completed in 2013, and the tower reaches a total of 104 floors. At 1776 feet, it is the tallest skyscraper in the Western Hemisphere.Learn more about Building Materials