Underground Warfare

We live in a world of competing nations and competing political ideologies. It is hardly surprising then, that Tunnellers built underground defense shelters, or that the USA is studying the use of deep shafts from which rockets can be fired; or that Russia is said to be building coastal caverns at Vladivostok to hide nuclear warships from satellite observation.

The history of many nations has included tunnels and underground networks as part of defense systems but none have been as significant as those of the Viet Cong in the war in Vietnam. From 1960 onwards, Vietnamese guerillas dug over 200 kms of tunnels around Cu Chi, connecting villages from Saigon to the Cambodian border. In these they slept, stored rice and explosives, and set up hospitals. These tunnels included air raid shelters that were cone shaped to amplify the sound of approaching aircraft. Each entrance was a concealed trap door protected by an armored guard. From these tunnels the Viet Cong eventually drove the US Army from Saigon.

The following extract was first published in ‘Storm Warning! #8’ on the 20th anniversary of the ’68 Tet Offensive. Based on the book The Tunnels of Cu Chi written by Tom Mangold and John Penycate, it pays tribute to the determination and ingenuity of the Vietnamese people.

 The Tunnels of Cu Chi

The Cu Chi area of what was South Vietnam, stands today as a monument to the heroic struggle of the Vietnamese people and as a fine example of how people, not technology, determines who wins a war.

The district of Cu Chi was the most bombed, shelled, gassed, defoliated and generally devastated area in the history of warfare. It was declared a “free fire zone” which meant that artillery fire fell on it at night and that bomber pilots were encouraged to drop unused explosives and napalm on the area before returning to base. In essence, anything that moved was considered a target and blown away.

Out gunned by the highest-tech military the world has ever seen and facing a U.S. government which vowed to bomb Vietnam back into the Stone Age, the liberation fighters had two choices: face defeat and accept foreign (US) rule, or rely on their determination and creativity.

Faced with fire from the sky, the people lived in tunnels by day and fought their war at night. There were hundreds of miles of tunnels in the Cu Chi area that connected villages, districts and even provinces. These tunnels held living areas, storage depots, ordinance factories, hospitals, headquarters and almost every other facility that was necessary for the National Liberation Front to wage its war against the U.S. aggression. This is one story of life in the tunnels. When a U.S. soldier was wounded in Vietnam he was often medi-vaced out of the battle area within ten minutes to be taken to a “base camp” hospital for emergency surgery. If further medical attention was needed, he was sent to a fully equipped hospital in Saigon or Japan. This was not true for the people that lived in the tunnels of Cu Chi.

In the Cu Chi area, the Vietnamese who were wounded were treated by people like Dr Vo Hoang Le. He was a Viet Cong Doctor whose working conditions were nothing like those in the giant U.S. hospitals in Japan. His operating theatre was a tunnel 8 feet high and 3 hundred yards long. A Honda motorcycle engine supplied his electricity. His instruments were made from the metal of downed helicopters. Instead of disposable polyethylene hoses, he had to use the plastic tube that coated electric wire for blood transfusions. He performed brain surgery with a mechanics drill, and amputations without the use of anesthetics. Even at the best-equipped hospitals there were few proper facilities for blood transfusions. Blood cannot be kept without refrigeration. Rather than be defeated by these conditions Dr Vo and others like him invented their own systems. “We managed to do blood transfusions” Vo said “by returning his own blood to the patient.” If a comrade had a belly wound and was bleeding, but his intestines were not punctured, we collected his blood, filtered it, put it in a bottle and returned it to his veins. While U.S. forces relied on massive bombing by B-52’s and strikes by Cobra Gun Ships, in the tunnels the people relied on their own ingenuity.

To quote VC guerilla Le Van Nong, “the Americans used their weapons to fight us and we used their weapons to fight back. There were unexploded shells everywhere in Cu Chi. We dismantled their detonators, fitted our own, and changed the shells into powerful weapons of which the Americans were very afraid.”

While U.S. forces relied on artillery support from fixed “Fire Bases,” the Vietnamese used their tunnel system to move their artillery around, making it difficult for the U.S.  troops to locate them. In one tunnel complex in Cu Chi, some U.S. GI’s found two 105-field pieces in perfect working condition. They would be stripped down outside, taken into the tunnels and assembled during the day for maintenance, stripped again, and then taken back through the tunnels to be reassembled in a new location outside and used again that night. A stolen tank was buried, tunnels were dug around it, and it was used as a command center. Three years later when GIs found it, the batteries, the lights, and the radio were still working.

These are only a few of the stories of the tunnels of Cu Chi. The U.S. spent ten years trying to smash not only the tunnels but the entire Vietnamese people only to be driven into the sea. Today the tunnels still stand, proof that the determination of the people and not technology can determine who wins a war.

Underground Tunnels to Infiltrate Commando Troops

On November 15 1974 a Korea-U.S joint team, at about 8 km northeast of Korangpo, discovered an underground tunnel extending from the north deep into Korean territory. In the tunnel, the joint team collected several pieces of Soviet-made dynamite sticks and a North Korean –made telephone, along with various traces indicating the tunnel was obviously dug by the North Korean Army.

The U.N. Command made a protest to North Korea and proposed that North Korea and the U.N. Command must conduct a joint investigation of the tunnel. North Korea rejected the proposal and insisted that it had nothing to do with the tunnel and that the tunnel incident was fabricated by the U.N. side.

The second tunnel of this kind was found on March 19, 1975, about 13km north of Cholwon. North Korea again denied its involvement. This tunnel, like the first one, extended from the north and ascended gradually toward the south, so that underground water could flow northward.

Around that time Kim Bu-song, a former member of the Liaison Department in the North Korean Workers Party, an organization responsible for carrying out anti-Korea operations; defected to Korea. In a testimony he revealed that he himself had participated in the tunnel digging as a compressor operator.

Based on information revealed by Kim Bu-song, the Korean Army was able to detect the third tunnel on October 17, 1978, extending down 4km to the south of the truce village of Panmunjom. The exit of this tunnel was only 44km away from Seoul, Korean capital.

On March 3, 1990, the fourth tunnel was discovered at 26km off Yanggu. These four tunnels proved that the North Korean Army had been digging tunnels all along the truce line.

North Korea still denies its involvement in the tunnel diggings. But it was revealed that the tunnel work had begun under the direct orders of Kim Il-sung.

On September 25th 1971, Kim Il-sung ordered Kim Jung-rim, chief of the Anti-South Korea Operations Department in the North Korean Workers’ Party, and Oh Jin-u, chief of the General Staff of the North Korean People’s Army, to complete the work of digging infiltration tunnels as soon as possible, saying, “Blitz tactics are the only means to enable North Korea to liberate South Korea, and one tunnel must be regarded as effective as 10 nuclear weapons”

North Korea imported advanced excavators from Sweden, and in May 1972, began to dig the infiltration tunnels across the truce line dividing South and North Korea. In February 1974, Oh Jin-u made an inspection tour to the front line area in order to spur the troops there to complete the tunnel digging projects as soon as possible.

North Korea has built these tunnels for the purpose of infiltrating commando troops deep into Korean territory, North Korea maintains so-called light infantry troops, which are armed with portable weapons, and trained to move swiftly in any terrain. North Korea is estimated to be still digging such tunnels all along the front lines. The Korean military authorities announced that signs of such diggings have been detected at about 20 spots.

The Maginot Line

During the period of 1929 to 1940, the Maginot Line was made in honor of a war hero, Andre Maginot, who was also a beloved Minister of Veteran Affairs and a Minister of War during the years 1928 to 1932.

The Maginot Line was so named because of Andre’s contribution of oration, which persuaded the parliaments, both the right and left, to allocate monies for the building of the fortification. It could have easily been named “Painleve Line” after the minister of war, who was responsible for introducing debate on the line in parliament, or the “Petain Line” after the gentleman who thought of the concept.

The Maginot Line was built to protect France from her arch-enemy Germany. It was used mostly as a place for the French Army to hide, and also to mobilize their forces. This made up for a shortfall of manpower that was predicted for the late 1930’s. It was the so-called “Great Wall” of France, a place where the nation could feel secure in its doctrine, which would later be known as the “Maginot Mentality”.

The Maginot Line was a powerful line of defence. It stretched from Switzerland to the Ardennes in the North, and from the Alps to the Mediterranean in the South. Most of the sections of the line were underground and the tunnels would interconnect and stretch for kilometers. In these tunnels thousands of men would sleep, train, keep watch and wait for the frontal attack that never came.

The Maginot Line was supposedly impregnable, yet it failed to save France from her humiliating defeat in 1940, and hence was considered by many, to be a failure.

BUT WAS IT? It still stands today over 50 years after it was built.

The line actually served its purpose for which it was built, it gave the French Army time to completely mobilize and deploy its troops. It dissuaded the German Army from attacking across the Eastern Frontier of France. If it was used properly, it could have made up for France’s anticipated manpower shortage. The major defect of the line itself was that it was too short and hence in May 1940 Adolf Hitler chose it ignore it.

The line didn’t actually fail France; the Maginot Mentality caused France her defeat, as did the refusal of the leaders to acknowledge the oncoming of modern warfare such as mobile battles that would be fought with tanks and aircraft. While France was busy building a modern version of First World War’s Hindenburg Line, Adolf Hitler was busy building Stuka Dive Bombers and Panzers.

The concept of the construction of the line came from France’s success in holding the trench line along 400 miles of its territory against the Germans and the failure of her pre-war doctrine of “The Offence”.  If France could hold off the Kaiser Army for at least 4 years with barbed wire and ditches, then why not adopt the same theory for a permanent system of defense along her borders?

The fortification was seen to compensate for the lack of manpower of its military defenses, and was also thought of as a possible tool to be used as areas of defense to repel the enemy long enough to build up reserves and materials needed to take the enemy head on.


By 1914, the task of fortifying the islands was complete. The Americans claimed that the defenses of Manila were strong enough to be called “The Gibraltar of The East”. During the 1920’s, although the Washington Naval Treaty of 1922 banned the construction of the additional fortifications, a huge tunnel complex was blasted from the solid rock of Malinta Hill. The main East West passage was 24 feet wide and 836 feet long, with 25 tunnels called laterals about 150 feet in length branching off from each side. At the end of one of these laterals, a further complex housed an underground hospital, while on the opposite side of the passage, another lateral lead to the navy tunnel system. Lined with reinforced concrete with fans to provide fresh air and a double track electric railway running along the main tunnel, Malinta tunnel became a huge bombproof shelter for the headquarters staff, workshops, personnel and stores.


Down Street Station

In common with many Londoners, Churchill sheltered from the blitz in a tube station-but one which had better facilities than most, including a private bathroom. The Chiefs of Staff to a Major Leslie Hollis who subsequently spent “many dreary days examining railway tunnels and old abandon railway workings” delegated the search for suitable wartime accommodation. Down Street Station was chosen as a possible shelter. Disused since 1932, the station was adapted in 1939 to form a small headquarters by walling off and partitioning the platforms. Once the bombing of London began in earnest, the occupancy of this bulk hole 60 feet below street level was shared between the Railway Executive Committee and Churchill.

It seems that Churchill, who referred to it as “The Barn” used Down Street not only as a retreat from air raids but also from the bustle and noise of the Cabinet War Rooms. He also ate there; his Private Secretary Sir John Colville, recorded one evening in particular in his diary when he “went to Down Street tube station where the PM was dining with Bevin. We penetrated to the bowels of the earth and extricated the diners. Bevin, who had been well plied with brandy, was extremely loquacious. He and I got into a lift together and had great difficulty in getting out, owing to his insistence on trying to open the gates before the lift had stopped. Then a policeman tried to arrest the PM for having too bright sidelights and was finally dismissed with a loud “Go to Hell, man”.

Churchill relinquished his access to Down Street in November 1943 when it was decided that he should use a different shelter, code name ‘Anson’ if bombing recommenced. The facade of the station is still clearly visible today on Down Street.

There were many other structures that are far too many to list, utilized as air raid shelters, communication rooms, etc. As the reader can now appreciate, bunkers and tunnels were used extensively throughout Europe and the Pacific. The Japanese had massive tunnel complexes at Papua New Guinea, which the allied troops found hard going to remove. Many still stand today as reminders of what can be archived when there is no price to remain free or protect oneself from the enemy.


After reading the above, one can appreciate that if tunnels and bunkers were in every theatre of war in Europe and the Pacific, it would not be hard for one to comprehend that the same activity went on here in Australia.

Our government was aware as early as 1929 that the Second World War was eminent. There were already WW1 tunnels and bunkers in strategic places. As in European and Pacific theatres, these WW1 structures were expanded onto or just simply reactivated. During our time of research, we have found documentation that clearly spelled out that the government at the time was aware by the 1930’s war was eminent It is a well known fact that the Australian Defense Forces at the time were poorly equipped. Unbeknown to the average Australian, defense measures were being taken.Even though the commonwealth thought the fall of Singapore was impossible, members of our government and trade unions could see that Australia, with its raw resources would or could become the next target for the Japanese. The Brisbane line was then drawn up, and the government at the time decided that they would give up sections of Australia to the enemy in order to regroup and fight them back. Another plan was also drawn up, which was called the Canberra Line. This is where the military would fall back to if the Brisbane Line failed. In preparation for both these defense lines, many tunnels, underground workshops, storage and magazines were built. The allied works council and the civil construction corps were contracted to build storage facilities and special operation rooms. It is interesting to note that when the Americans entered the war in 1941, they moved straight into some massive underground headquarters/ storage facilities/ workshops upon arrival in North Queensland.

Our company holds restricted military photographs dated July 1941, showing large portals in various strategic places throughout Australia. The question must be asked, “If the governments in other theatres of war were preparing underground defensive structures, why would our government not follow the same strategy?”

We know by archival material obtained, that the official undertaking of large-scale construction of subterranean & semi-subterranean structures was well underway by the 27th of April 1940. With the arrival of the Americans, in 1942, with large amounts of the United States lend-lease materials and servicemen and technology arriving and with it now clearly in the allied minds, that Australia was going to be the next major target of the Japanese. With the American government utilizing Australia, as a step off point for the battles in the Pacific, and with the Japanese bombing of Darwin, the mammoth task of building subterranean structures, as seen in the European theatres, had commenced on the same scale here in Australia. Even though it has been hotly debated, that structures of the same scale as seen in Europe, could be built here in Australia, for the first time in 60 years. ABMM has produced military photos clearly depicting very large-scale bunker systems here in Australia (see photos). With the Americans utilizing Townsville as their staging point for the Pacific, the 5th / 4th Air Depot was built at a rapid rate. This base was the largest American base outside the US during the 2nd World War. Our research has shown, that 90% of the secret underground bunkers were under the control of the US military, with the exception of Castle Hill in Townsville, being utilized by the Australian 11th squadron stores, who used a section of the bunker at Castle Hill, for the storage of equipment. This was unusual as the US Military had ACH Headquarters inside another sector of this bunker. (See blueprint).

The 5th Air Depot, was the major staging ground for the Battle of the Pacific, and given its strategic military position, had many large underground tunnels and bunkers, including, underground fuel and oil tanks hidden from the enemy. Its interesting to note,

that when the US military first arrived with the LTC’s, that there was equipment and supplies, sprawled for miles on the beach at Jezzine Barracks, as well as mountainous piles of equipment at the docks and railway yards. But in all the photos ABMM has ever had donated or purchased, this equipment simply vanished in a short period of time. Every photo that ABMM holds, of the Butler Hangers, shows no equipment, on near or in any of the service hangars. It is interesting to note, that in almost any other military base, during this period, stores and supplies, were in full view during the same period. So one must ask, “ Where did all the equipment go, if it was not in the facilities, in or around Townsville?” The photo that is shown is of the 5th Air Depot, clearly showing portals behind the motor pool.

The United States 4th Air Depot Group moved from Melbourne, arriving in Townsville on 2nd October 1942. They formed Depot # 2 of the Service Command.

The Service Command was responsible for assembling, modifying, overhauling and carrying out major repairs on aircraft.

No. 2 Depot was established at the base of Mount Louisa not far from Garbutt aerodrome. Townsville was chosen because of its nearness to New Guinea. Aircraft was able to carry out bombing missions to New Guinea from Townsville. Other factors were Townville’s port facilities and its access via the rail network.

There were 35 igloo type buildings erected at the base of Mount Louisa. The Depot comprised repair shops, stores, and numerous aircraft engine test stands complete with soundproofing. Wartime photos show an extensive road network through the bush connecting all of the buildings, etc.

The Depot was initially built by the US Engineering Corps, but was later taken over by the Allied Works Council.

Living quarters comprised over 120 large barrack type buildings plus 3 or 4 tent cities. There was also an extensive sports ground in the vicinity. (see photos)