The Former RAAF Explosives Storage Area includes a number of historic structures associated with wartime activities such as the traverse, bomb service and proof annexe, and 12 Armco Shelters. All but two of these shelters are set into the contours of the hills. They are all Armco barrel vault constructions, some internally strengthened with tramway rails, possibly from tracks used at mines throughout the Territory at the turn of the century. Shelter No. 5 carries 12.7mm diameter projectile entry and exit points which have been attributed to Japanese strafing by Mitsubishi A6MZ "Zero" or Nakajima Ki-45 "Nick" which used 12.7mm weapons in air attacks on Darwin.