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.
Reminds me of an ancient bad joke
What's the difference between school and prison
Schools don't have bars on the windows