Charles Darwin National Park contains rich natural and cultural resources including protected bird species, middens and mounds, and historic structures associated with military activities. The presence of historic structures dating from the Second World War and activities associated with the Indonesia-Malaya Confrontation and the Vietnam War are a reminder of the continuing importance of Darwin to the northern defence of Australia. This precinct includes semi-buried steel shelters constructed during the defensive build up in the north in the lead-up to World War II, a proof testing and servicing facility that was developed to meet the rapidly changing technology of the post-war period and a series of international incidents, including Confrontation and the Vietnam War. The site of the pre-war buildings in the Explosives Storage Area was strategic and the effectiveness of both the site and its camouflage ensured that it operated effectively throughout the 46 recorded enemy raids of the war years. Building No 5 is the only one of the Armco shelters known to have sustained damage as a result of enemy action, almost certainly during the raid of 20 June 1943.