These look a lot like the tunnels that are left at Washington University in St. Louis. Many of them have been torn up as new buildings are put in. I'm convinced that my friends & I were among the last people to be in one of the tunnels, as it was demolished the week after we were there. A single tunnel that used to run the entire 3/4 mile length of the campus is now just a few fragments. When we had the presidential debates here, the secret service stationed agents in the tunnels, as some of them lead into the athletic complex (where the debates were being held). Most of the tunnels are the old, narrow, short kind, filled with pipes. There is 1 new tunnel on the north end of campus that's big enough to drive a golf cart through, though -- there's even a driveway leading into one of the buildings! Last time I was there, 2 years ago, you could still get into the tunnels through a manhole cover. I can't imagine that they locked it (too thick), but it is really heavy -- scary sealing yourself in when you go down the ladder.