The Japanese Barge Tunnel is one of Rabaul's more tangible Second World War sites. Japanese forces dug tunnels into the volcanic landscape around the harbour to hide boats, supplies, and equipment from Allied air attack, and the barge tunnel preserves that improvised military logic in a way that is easy to grasp.
It is a short, atmospheric stop rather than a large museum. The darkness, rough walls, and surviving stories of concealed craft give Rabaul's wartime history a physical edge that complements the town's volcano viewpoints and harbour scenery.