A society devoted to the study and investigation of man-made and man-used underground places.

Founded by a group of journalists, historians, architects, and planners to campaign publicly for endangered historic buildings.

Saving historic and redundant places of worship from demolition and decay. Photos and details included.

Napoleonic fortifications and underground tunnels of Kent.

North Wales caving club. Souterrains, man made underground objects, artificial cavities, mines, quarries, tunnels.

Disused stations in London, England's underground.

Discover the hidden side of Glasgow through photographs, maps and images. Subterranean Glasgow, buildings, architecture, photographs of the city.

A commercial site promoting paid tours of a bunker near St. Andrews.

Urban exploration in the south east of England, concentrating primarily on subterranea also featuring building explorations.

A guide to using Internet-based research tools to reveal the UK's hidden MoD facilities and military sites.