Although most of the Japanese defense forces were
underground in 360 miles of tunnels dug into the volcanic mountains surrounding
Rabaul, some command posts and related bunkers were engineered as reinforced concrete
fortifications on the harbor coastal rim.
Admiral's Bunker, had extensive living, command and communications facilities
in it and was in post-war years converted into a museum. Unfortunately, it was
covered with ash during the severe 1994 volcanic activity and may be some time