09.26.14 :: Fort Amherst, constructed in 1756 to protect the River Medway and Chatham Dockyard from Napoleonic invasion. The construction of the Tunnels seemed like a really good idea due to earlier attacks on the dockyard in 1667 by the Dutch. No invasion ever occurred from the French. The Tunnels were used as a post of operations during WWII. 
natural chalk walls
