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.
It’s cooler underground because it’s well insulated. That also means it’s incredibly difficult to get rid of any waste heat. With artificial lighting, electronics, hell even just people moving around, that’s a ton of heat being out that needs to go somewhere. Not to mention the amount of ventilation that would be required just to have breathable air. Are you imagining people driving around on underground roads?