One World Trade Center - Chicago.

This is were I work. I'm reminded every day of 7 years ago. This building is better know as the Merchandise Mart.

The Merchandise Mart is the world’s largest commercial building, largest wholesale design center and one of Chicago’s premier international business locations. Encompassing 4.2 million gross square feet, The Mart spans two city blocks and rises 25 stories. It even has it's own post office and zip code.

Here is a link