So I just discovered today that there’s a room in my house that I didn’t know about! It’s a storage room in the basement that is only accessible from the outside. I had seen the half-height door, but I knew where the door to my basement was, and I knew this wasn’t it, so I had just assumed it went into my neighbour’s basement. I was chatting with her today about some other stuff and she mentioned “your [i.e. my] little storage room” and I needed her to explain. Cool! It’s evidently not too dry, but it has a concrete floor and it’s reasonably sizable. It probably has almost as much usable storage space as the attic space over the garage, and has the huge advantage that I don’t need to climb a ladder to get to it. Score!
My neighbour has been trying to sell her place. If she’d moved out before mentioning that, I might well never have discovered what was behind that door.