Recreation, Outdoors, Speleology, Wild Caves - Ogof Ffynnon Ddu. Features virtual tour of the OFD system located in the Upper Swansea Valley in South Wales.
Recreation, Outdoors, Speleology, Urban Speleology - Dark Passage. A New York based organization providing blind archaeologists with the finest quality flashlights.
Recreation, Outdoors, Speleology, Urban Speleology - Avatar-X's Urban Exploration Resource. A website dedicated to urban exploration in Canada and other areas, with many image galleries and stories, and an active urban exploration forum.
Recreation, Outdoors, Speleology, Urban Speleology - Portsdown Tunnels. Researches and records the above and underground sites on Portsdown, Portsmouth, UK.
An urban exploration social network and reference site. The website with an interest in anything secret. Secret underground cities, classified military instilations, cold war nuclear bunkers, WW2 secret underground ammunition stores and underground factories.