In Mendig (Eifel) there is an enormous mine for millstones which was in us for the whole middle age until the 19th century or so.
Most people just dug down from their Celler and the whole city stands on enormous caverns.
Haha good catch.
I actually did some dsa campaigns inspired by these caves. They are super still, cold and eerie. Most of the shafts are filled today but you can see how dangerous they where. Small steps, without any guardrails, often slippery because water leaks in die to cracks in the rock. Also, many caverns are big, because they excavated the stone but the access tunnels are super small and steep.
