Europe's largest prehistoric mound – burial site of a legendary king?

In an isolated field near a dilapidated barn stands this chilling portrayal of the plight of the Nuba peoples of Sudan.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.