A few weeks before the four stacks were demolished, I took a few visits to the site to see how preparation was going and what had been done to the building. There were piles, and piles, and piles of piping, ductwork and general scrap littering the south side of the building as the process of emptying the structure slowly moved forward. We had seen the enormous scale of the infrastructure inside the building but once it was removed you could experience that close up. This duct or vent pipe is nearly 15' tall.