Not general areas, but particular spots
I'm waiting for the coffee to kick in.

Some weird places I've been:

1. Inside a WWII coastal defense bunker in Pacifica, CA on Milagra Ridge. While I was growing up, every now and then someone would manage to get the huge steel doors open and hiking passers by would go inside and ooh and ahh. There was thirty years of graffiti, still sparse since it was open so seldom, and the remnants of small fires (charred blankets, marks on the walls). Some of the larger and more difficult to remove things still remained, like parts of the old generator and such. One time it was me and my friends who opened it. We went through a lot of hacksaw blades sawing away at the hinges. It's now welded shut so thoroughly that you'd need a generator or a ton of batteries for your cordless grinder to get inside. There's also a decommissioned Nike missile site nearby, evidenced from above only by a slab of concrete and the access hatch. I popped the welds once on that hatch with a woodsplitting wedge and a five-pound sledgehammer and went down with some friends, though I'd been down before with my dad and sister before it had gotten welded. You could still see the undersides of the twenty foot long steel doors, though the missile rack was gone. You had to climb down a 15 or 20 foot ladder to get down to the main concrete floor, and though there were steel grate stairs heading down yet further near the ladder, the lower part was flooded. It was so still and the water so clear that it was a little difficult to see exactly where the water level began. The funny thing about that site is that it was active in my lifetime: a neighbor farther up my hill with a view of the site from his kitchen reports having seen (through binoculars) the rack, loaded with missiles, come up and pivot to where it was pointing at his house. The doors are covered in concrete now and the hatch is very thoroughly welded.

2. The office of the president of the Cleveland branch of the Federal Reserve Bank. The moving company I worked for in the summer of my Junior year of college had the contract to move the contents of the building, floor by floor, to a nearby secondary office and back again as each floor of the main building got renovated. I was there when the president's desk, a giant cherry monstrosity, got moved back in. That office had twenty foot ceilings and it was frigging huge. It's not on the tour.

3. The top of Seoul Tower in Seoul, South Korea. That's not so weird since anyone in Seoul with a few wan can get up there, but it's still a bit neat. At the time, for security reasons, you weren't allowed to even bring a camera up there, much less take pictures. I had one of those little clamps-onto-a-110-film-cartridge cameras on me that I'd forgotten about. I was not arrested.

4. Some steam tunnels underneath the quad on CWRU's campus. It was a relatively short tunnel—I never got into the main complex, which I hear is very extensive.

5. The stage of Severance Hall, where the Cleveland Orchestra plays. A friend of mine had found a window that got left unlocked at night and we snuck in. I plucked the cello and fondled some other instruments. We toured pretty much the entire building, basement to roof.