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.
The ESO New Technology Telescope (NTT) is the precursor to modern dome design, with an efficient use of space and ventilation. It pioneered active optics, with actuators deforming the mirror to achieve optimal image quality.
It also looks fairly evil from this angle. This is at La Silla Observatory, Chile.