Down on the waterfront, not far from Old Town Tallinn, sits a crumbling old building first built as a cannon battery in 1842. This is Patarei. It was later turned into a prison, and operated as such until it finally closed in 2006. Now the government has thrown the doors open to the public. For two euros you can wander around inside, pretty much at will. This has to be one of the dankest, gloomiest places I've ever been. The first floor was so clammy even on a warm summer day that the walls were dripping wet. It was fun to spend an hour or so wandering around. I'm glad I never had to live there.