What's this giant patch of nothing on the south side?

[ScatteredFrog]

What I mean is this...

I was doing some research for work, and I typed in 8255 S. Houston into Google Maps. If you look at the satellite view and move east a little bit, there's this huge mass of what looks like a long-abandoned airport or something. It's bordered by 79th Street on the north, Brandon Avenue and Green Bay Avenue on the west, and the lake on the east.

Now...due north of that there's something labeled "Rocky Ledge Park," but I doubt that whole massive area is the park.

What is that thing?? What used to be there?? Was it steel mills or something at one point??

[Dinsdale]

US Steel South Works.
Over the years there have been any number of plans for the space, but they never seem to come to fruition.