It is believed that as many as 400 men helped build the tunnels. Conditions were difficult and industrial action slowed the construction progress. Only five of the tunnels were completed when the war ended.
The tunnels were never used for bulk oil storage, although aircraft fuel for the RAF and RAAF was stored in tunnels 5 and 6 in the 1950s.
Although concrete and steel lined the tunnels, it was apparent in 1945 that the tunnels leaked. The water seeped between the steel and concrete, creating corrosion and it was deemed too expensive to fix. After a period of heavy rain, the system became inoperable.
Allow 30-45 minutes for this self-paced tour. Interpretation boards and photos line the tunnel walls providing fascinating insight into Darwin's rich history. Books are for sale at the entrance and the knowledgeable gate keepers are available to answer any questions.