The City of Caves

The city of Nottingham is built on sandstone, which is a soft stone, easily "worked" and so from time immemorial people have burrowed in to it to create caves - to live in, or store stuff in or for shelter and the like.  The caves are now a money-spinning tourist attraction and are protected as "scheduled monuments".  There is documentary evidence that in the Middle Ages some caves were used as tanneries, and in the last war, they came in very handy as air-raid shelters.  You can take a guided tour and learn all about them.