I am oddly fascinated by abandoned buildings, particularly those that had a specific purposes in their former lives—factories, military bases, theme parks (although those aren't really just buildings). I found this list of abandoned observatories a while ago, and meant to share it with you then, but it got shuffled to the bottom of my drafts list. (Apologies!)
I would love to explore these buildings, regardless of the dangers their aging construction might pose.
But I would do it in the daylight. I've seen too many bad horror/sci-fi movies to want to visit a place like this in the dark.
Do you have a fascination of this (strange) sort? I'd love to hear about it!