WWII Navy Oil Storage Tunnels no 5 and 6.
This system consists of two oil storage tunnels beneath the south-eastern edge of Darwin city. The tunnels have a total length of 673 metres and each is 4.5 metres wide and 5.4 metres high. The tunnels are horseshoe shaped in cross section and have welded steel lined walls and a concrete floor. Entrance tunnels and chambers are separated by bulkheads for pumping equipment and working spaces. The tunnels are connected to the Darwin Wharf area by steel pipelines.