Marble Bar airstrip is 36 kilometres south of Marble Bar in Western Australia. The airstrip is one of few remaining remnants from Australia’s involvement in World War II. The Marble Bar airstrip was heavily camouflaged and carefully hidden, known also as No. 73 Operational Base Unit, or Corunna Downs.
The runways were built for the heaviest four-engined bombers of the time. Prior to the upgrade, the main runways which were 1650 metres and 2300 metres long and 50 metres wide were originally constructed with bitumen surfaces, had become cracked and parched.
During the war, 300 service personnel were stationed at Corrunna Downs and lived in tents surrounding the airfield where temperatures sometimes reached 50C. The base provided a strategic advantage to the war effort because aircraft could target Japanese bases without having to fly over Islands north of Darwin that had been taken over by the Japanese. This alternate route over the sea gave the aircraft the element of surprise. Every effort was made to keep the airstrip concealed during the war, with regular Japanese reconnaissance aircraft searches. The base and its highly secret operations were never mentioned in the press or radio reports.
The Corunna Downs base was officially closed on January 14, 1946.