This is where the Japanese Navy, under Rear Admiral Ota, took its last stand in the Battle of Okinawa. A system of underground tunnels stretching 450m (1,475 ft.) and built by civilians using shovels and pickaxes, it remains almost exactly as it was, including the operations room and where Ota killed himself with a grenade. Rather than surrender, many of his staff also committed suicide; 2,400 bodies were eventually recovered after the war. Before touring the tunnels, which are rather bare but convey what it must have been like to live here (audio explanations throughout the tunnels are available in English, but you have to request them to be turned on), first tour the one-room museum. Most poignant are farewell letters written to family members.