Underground Kent
Recreation, Outdoors, Speleology, Urban Speleology - Underground Kent. Napoleonic fortifications and underground tunnels of Kent.
https://www.undergroundkent.co.uk/
Hidden Glasgow: photographs, images, Glasgow history, culture, regeneration
Discover the secret and hidden side of Glasgow through photographs, maps and images. The Hidden Glasgow Guide to Glasgow's undiscovered side - a community site about Glasgow's: photographs, images, history, culture, chat, forums, banter, subterranean Glasgow, buildings, architecture, photographs of the city and lots more
http://www.hiddenglasgow.com
Friched.net
Recreation, Outdoors, Speleology, Urban Speleology - Friched.net. Features urban and industrial photography around Paris.
https://www.friched.net/
Derelict London Intoduction Page
Recreation, Outdoors, Speleology, Urban Speleology - Derelict London. Snapshots of the Capital's urban decaying beauty: graffiti, buildings, waterways, cemeteries, people, murals, pubs, vehicles, disused tube stations.
https://www.derelictlondon.com/
Urban Explorer of Buffalo
Recreation, Outdoors, Speleology, Urban Speleology - Urban Explorer of Buffalo. A site devoted to urban exploration in Buffalo and Western New York.
http://www.buffaloexploration.com/
Urban Exploration - Undercity.org
Recreation, Outdoors, Speleology, Urban Speleology - Undercity.org. Steve Duncan's site features photography of underground or unknown sites in New York.
https://www.undercity.org/
Hudson Valley Ruins by Tom Rinaldi & Rob Yasinsac
Recreation, Outdoors, Speleology, Urban Speleology - Yaz's Hudson Valley Ruins. Features many historic and contemporary photographs of structures along the Hudson, including Bannerman's Castle, and Briarcliff Lodge.
http://www.hudsonvalleyruins.org/
Ars Subterranea
Recreation, Outdoors, Speleology, Urban Speleology - Ars Subterranea. Comprised of artists, historians, architects, and urban explorers wishing to create an intersection between art and architectural relics in New York City.
http://creativepreservation.org/
Allied Paper: An Abandoned Paper Mill
Recreation, Outdoors, Speleology, Urban Speleology - Allied Paper: An Abandoned Paper Mill. Photographic tours of, and information on a large abandoned paper factory in Kalamazoo, Michigan.
http://www.alliedpaper.org