I've always been curious about the cellar/underground rooms before.
How do you stop it from flooding though?
I have owned several buildings with cellars and finished basements. Depending on the geography, water table and rainfall amounts, a big hole dug in the ground under a building, with no natural drainage, will require drains or pumps to remain dry.
My last house had a basement that was usable underground space but that was due to an extensive "French drain" system as well as a separate drain system against the concrete foundation and land sloping properly for good drainage.
The first house I owned that had a cellar also had a sump w/pump that kept it dry. I accidentally turned the pump off and a good soaking overnight rain resulted in the 25x35 cellar filling with water to the rafters. I had to turn off all power to the house and dive under water to reconnect the pump to power.
That is a lesson one only makes one time in life.
lots of fishing hooks on fishing wire suspended just inside the door. Won't stop anyone breaking in, but when they get entangled they'll wish they weren't a thieving git.
Just have to remember yourself that it's there and be careful
