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.
It was built in the 70s, and there is plenty of other brutalist architecture in Bloomington because limestone and brutalism work well together and Bloomington is surrounded by limestone quarries.
But I still think that's a little over the top evil for a middle school.
I mean the IU main library across town has no windows and looks far less evil.