I have seen many places all over eastern europe like this, but maybe not quite so awesome as this one. Bulgaria is full of ramshackled old buildings standing idle. A friend of mine called Kamen showed me photos of a former munitions factory that stands empty now, up for sale, and a hotel, also. For 3 months I was sleeping in a power distribution room that I was able to lock up, underneath the central park of Sofia, and it was warm enough down there for me to get through a january that had temperatures that fell to -15 degrees. This tunnel was locked up, fortunately after the worst of winter was over, and is now inaccessible. At least not easily accessible. I think there probably is ways to get inside it still. A monument that still stands in the middle of that park, stuck half way through demolition, has sheltered spaces inside it that people were sleeping in as well.