World Trade Center

The World Trade Center were the tallest buildings in the world when they were built. The North Tower was 1,368 ft. high, and the South Tower was 1,362 ft high. The difference in height was because the Port Authority wanted the 43rd and 67th floors of the North Tower raised a few feet. The 43rd floor was a cafeteria for Porth Authority workers. The South Tower didn't need any floors raised so it stayed at 1,362 ft.

The Twin Towers had a "rigid hollow" tube of closely spaced steel columns with trusses that extended to the central core which held the floors up. The columns were 18.75 inches wide and were spaced 22 inches apart which is why the towers looked like they didn't have any windows at all. The outside columns were used to resist the lateral forces including wind and earthquakes. The architect Minoru Yamasaki wanted to use columns that were spaced closely together to make people feel safer when they were at the top of the buildings.

Windows on the World was a formal restaurant that covered 50,000 square feet of floor space on the 106-107 floors of the North Tower. The restaurant had revenues of $37.5 million making it the highest grossing restaurant in America.

There was an observation deck at the top of the South Tower of the World Trade Center called Top of the World. The visitors watched a simulated helicopter ride through Manhattan. If the weather was nice, visitors could go up to the highest outdoor observation platform in the world on the roof.