13 Years After 9/11, World Trade Center Reopens for Business
Standing at 541 meters with 104 floors, it is officially America’s tallest building and cost $3.9 billion to put the skyscraper together.
     
 The new World Trade Center is the center piece of the 16-acre site where the twin towers once stood, before they came crashing down, killing more than 2,700 people.
The old twin buildings went down on September 11, 2001 after it was hit by two planes hijacked by terrorist group, al-Queda.