How about them Cowboys!
Same guys who did WTC 7? 
My theory is that it was the Purple People Eaters.
I live about 3 miles from Texas Stadium. The rubble is all still there. The first day there were so many rubberneckers on the adjacent highway that it literally stopped traffic as people gawked at the remains.
And no, Hardball, it was “Weir Bros Demolition.” I don’t think those guys get Black Ops contracts…