I grew up in an underground house, though not one as elaborate as this sounds. It was mostly just a concrete house built into the side of a hill so that only t

I grew up in an underground house, though not one as elaborate as this sounds. It was mostly just a concrete house built into the side of a hill so that only the southern face is exposed. When my parents moved in it had four feet of earth on the roof as well. The roof would be dry the day it rained, but would start leaking two or three days after the rain was done. They got tired of that. So they removed all the dirt and exposed the concrete, then just built a second story onto the house. The main peculiar thing about that house from a broader perspective is that we treated the upstairs like most people treat a basement. The main room in the upstairs was I think 20 feet wide by 60 feet long. And it had a concrete floor. Made for a good adolescent play area.