I recently got to see the backrooms of an MIT building in sub basement 2. You had to go through some tight spaces (think ~20") and there was some rotating mach

I recently got to see the backrooms of an MIT building in sub basement 2. You had to go through some tight spaces (think ~20") and there was some rotating machinery to stay away from. I was surprised at how big it was. When I first went in I thought it was just the narrow corridor with the large air handler units, but it snaked around a corner to reveal itself to be 4-5 times that size. The entire MIT campus is connected through underground hallways, most in use as labs. It's not all in ship shape, but tunnels and underground labs and industrial machinery do entertain my inner child. I've heard UWisc's steam pipe service tunnels are cool to see, but I never got a chance to explore them while I was there.