Jack Cade's Cavern is a cavern, extending several hundred feet underground, in Blackheath, south-east London, England. It is located northwest of the Heath and southwest of Greenwich Park, mostly beneath the lawn of Hollymount Close. It was re-discovered in about the year 1780. They are also referred to as the Blackheath Caverns. The entrance was at the end of a row of small cottages called "Cavern Cottages" at the rear of Trinity Church on Blackheath Hill, (destroyed in WWII). Dimensions Entered by a flight of forty steps, it consisted of three or more separate caverns joined to one another by tunnels. The first or main cavern is roughly circular and about in diameter. Leading from this is another about . There is a long, winding passage leading to a chamber which is about , varying in height from to , with a well of pure water, in depth, although in 1939 this was found to be , partly brick lined and quite dry. At its lowest it is from the surface. Further reading History of Lee and its Neighbourhood by F. H. Hart pp. 90–91 Perhaps this has best description of the cavern. Kentish Mercury Almanac, 1903 The Ambulator, 11th edition, p. 49 Underground passages, caverns, etc. of Greenwich and Blackheath, a lecture by J. M. Stone to the Greenwich Antiquarian Society, 26 February 1914 Notes and references External links www.shadyoldlady.com The location of the last known entrance to Jack Cade's Caverns. Greenwich Industrial History Society Mr Budd & The Temple of Doom by Tony Lord Printed 1810 copy of original survey made in 1695, drawn by Samuel Travers Buildings and structures in the Royal Borough of Greenwich Caves of London Geography of the Royal Borough of Greenwich Air raid shelters in the United Kingdom Blackheath, London