Confession: I have a minor obsession with abandoned places. The more crumbling, overgrown, and full of dangerous bits of rusted metal or roofs in imminent risk of collapse, the happier I am.
Here on the New Hampshire Seacoast, I've managed to squirm my way into some places I am patently not allowed to go (and will therefore not list here in a public forum).
Maybe it's the same reason I'm nuts for archaeology. Crawling around the ruins of modern society's abandoned places really isn't all that different from exploring what's left behind when other cultures and societies fade away or move on. Inhabited, maintained spaces have their mysteries, of course - my lit fic cohorts love to explore those, in all their twisty emotional glory - but they don't sing out at you like those in deserted places.
That's also why the same thrill never seems to apply to ruins that have been put on a tour bus circuit. Add ticketing, add other camera-toting people, add legitimacy, and my interest wanes. I want to feel like I'm the first person in an era to set foot inside these places. I want to imagine that I'm making a discovery.
On the Aran Islands off the west coast of Ireland, there are a series of Iron Age ring forts. One has been turned into a museum, complete with informational signs and easy accessibility. Of course, the one that I fell in love with could only be reached by hiking for over a mile across a barren landscape of exposed, windswept bedrock, following the line of the cliffs and a single extremely vague signpost.
Here are three of the spots at the top of my probably-illegal exploring wish list:
North Brother Island, New York: Those who manage to get to this island in the East River without getting arrested can enjoy stunning views of downtown Manhattan and thirteen acres of decay, including a crumbling former quarantine hospital and roads completely buried in kudzu. RadioLab (lovethemsomuch) managed to make the trip and wrote about it here.
Portsmouth Naval Prison, Maine: This gloriously gothic ruin sits oh-so-temptingly in my own backyard, on the outer edge of Seavey's Island. Sadly getting there means trespassing on federal property - a naval base that now works to upgrade our nuclear submarine fleet. Needless to say, security is tight. I can't direct you to images of what it's like, because if anyone has been inside, they're not admitting it, but here's a desperately intriguing video of someone boating around the exterior, before they (very likely) got chased off by the harbor patrol.
Burlington, Corsham, UK: A thirty-five acre underground Cold War-era bunker city, built to basically whisk the core of the UK government beneath the streets in the event of a nuclear attack. It was actually maintained as 'active' government property until 1991, when the space was finally decommissioned. It's closed to the public, but you can gawk at piles of gorgeous photos thanks to the BBC.