Underground housing, underground businesses, etc. Would that be better for the environment + possibly save on energy costs? Also possibly safer in certain scenarios like tornadoes etc.
Potential issues that immediately come to mind are ventilation, earthquakes, and flooding. But it’s not like underground dwellings/basements/etc. aren’t a thing, so maybe those issues have been addressed in ways I’m not familiar with.
I also read about a psychological study of living underground reported by DW News, and the sense of time lengthens when you’re in the dark caves for a long period of time. Really interesting I think! This kind of thing would mess with our Circadian rhythm