I like caves, I like tunnels, I like the dark dank damp dusty musty and forgotten realms that lie beneath our large buildings.

I just don't like them enough to take my life into my own hands and go meandering about semi-collapsed abandoned mines.

Not these guys, though. Check out The Breaker Boys, as they explore man-made subterranean caverns and abandoned buildings here in NEPA.

There's an entire web-ring devoted to fool-hardy people (fool-hards?) like this. I envy their guts, and think about my claustrophobia.....
When I was in college (waaaaay back when), one of the central building underwent expansion, and the tunnel system was exposed. After we finished our late-shift in the kitchen, another student-worker and I snuck in a couple night in a row. Big concrete tunnels, laid down in the sixties for heat, power, etc—large enough to drive a large truck through, big empty rooms, piles of student desks, an old steel coke can that I still have, crumbling brick tunnels from the original structure built in the 1860s, and somehow we ended up inside of the power plant. We saw a guy's feet on the gridwalk above us, and we skedaddled. Came back into the plant from the outside—this was now around 2am, and introduced ourselves. Guess the night guy didn't get too many visitors--he showed us around for the next two hours, all the nooks and crannies, even fired up the coal furnaces (that heated the entire campus) for us. Stealth and sneaking can be cool, but so can (relative) honesty, as well.