This huge concrete pad seems kind of random. The pedestrian walkway is supposed to be to the right of this pad, so I'm not sure what it's for. Earlier in the day, works were drilling holes it seems like.
Also, the first couple of pizza-shaped window planes were put up. It looks like they were checking out how it looked/showing it off. Probably looks better in the morning.
Edit: Actually, these windows have been up since June 17th but they only just now showed them off for more than an hour, otherwise I probably would have never noticed them.
http://www.districtdetroit.com/live-web-cam/