Here. And here is a photo slideshow.

An exceprt:

Even among the elite class of ironworkers that specializes in raising high steel, the 40 or so men who perform the most dangerous work at 1 World Trade are a kind of special forces. There are veterans like Turhan Clause, a 46-year-old bolter-upper and an Algonquin Indian whose father and grandfather were also in the trade.