21. Case 17: One World Trade Center

One World Trade Center (One WTC) is the main building of the rebuilt World Trade Center complex in Lower Manhattan, New York City. This new structure has the same title as the North Tower of the original World Trade Center which was destroyed in the terrorist attacks of September 11, 2001. One WTC is the tallest building in the United States and the sixth tallest in the world. The steel frame of One World Trade Center is higher than the 1250-ft-high Empire State Building which is the second tallest building in USA. The building has 94 stories with the top floor numbered 104. It occupies approximately 3 million square feet which includes 2.6 million square feet of new Grade A office space spread across 71 floors. It is most expensive new office tower with cost exceeding $3.8 billion. The tower’s construction consists of steel and concrete.