Today marked a momentous occasion as for the first time 13 years, the World Trade Center is back and officially open for business. Magazine empire Conde Nast moved in to the One World Trade Center with it's 2,300 employees set to be spread among 24 floors. At 1,176 feet, the 1 WTC is now the tallest building in the United States. The tower is 104 stories tall an has a 3 floor observatory that will open in the spring. The 1 WTC and it's 16-acre site are owned by the Port Authority.  The 9/11 Memorial officially opened on September 11, 2011. The 9/11 Museum opened six months ago.

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