Batchelor Middle School in Bloomington, Indiana, USA.
Ironically, there were very few walls inside. Classrooms were separated by accordion dividers which could be pulled back to connect three classrooms into one big classroom. There were no back walls to these classrooms, just a huge opening at the back. I'm told that's been changed in a renovation.
I didn't go to Bachelor, but had friends that did. One of my youth football teams practiced in the fields there and yeah, I always that Bachelor looked like a prison.