The Cu Chi Tunnels were built in an area of heavy guerilla resistance, known to the Americans as the Iron Triangle, from a system of tunnels originally constructed as hiding places and links between villages in the 1940s by
guerillas fighting against the French. The red soil in the are was hard and compacted, and ideal for digging tunnels that didn't collapse. In the gap between French occupation and the arrival of the Americans the tunnels
fell largely into disrepair, but the area's thick natural earth kept them intact and maintained by nature. [Book: The Tunnels of Cu Chi by Tom Mangold and John Penycate (Random House, 1985)]
The Viet Cong enlarged the tunnel system in the 1960s and began hiding entire military units in them and used them as command center for guerilla activity in an area that became strategically important. It was a fortunate stroke
of luck for the Viet Cong that the South Vietnamese government constructed many "strategic hamlets" near Cu Chi, which provided the guerrillas with new recruits and support and means of spying on their enemy.
AFP reported: “Communist forces in the 1960s expanded tunnels that anti-colonial rebels first built in the late 1940s, creating a vast complex with sleeping quarters, arms caches, kitchens, hospitals and even propaganda theaters.
Entrances were concealed and booby-trapped to stop the "tunnel rats," US and Australian soldiers of narrow build, who crawled into the deadly holes with only a torch and a handgun to ferret out the black pyjama-clad enemies.
The elusive underground guerrillas -- once dubbed "human moles" by US commander General William Westmoreland -- terrified US and South Vietnamese forces like no other communist soldiers in the conflict. [Source: Agence
France Presse, January 29, 2008 <>]
“Viet Cong veteran Nguyen Thi Nghia, who joined the revolution when she was 13, recalled how her village "went underground" and how she once spent five days in a hot and claustrophobic tunnel during a heavy bombing raid. "The earth was swaying like a
hammock," said Nghia, 61. "We were crouching in the tunnels with only one candle. We tried not to speak to save oxygen and limit carbon monoxide. We tried not to move. We were soaked in sweat."” <>
Tunnel-based guerrillas launched hit-and-run attacks. The Communist presence in Cu Chi was so pronounced that the Viet Cong staged victory parades in the villages there. The Americans were infuriated that an area so close to
Saigon could be so overrun with the enemy. Activity in the Cu Chi area was one of the main reason why the Johnson administration decided to step up American presence in Vietnam. The Cu Chi District is known nationwide as
the base where the Vietnamese mounted their operations of the Tet Offensive in 1968.
For many years the Americans weren't aware that the tunnels existed. When they were discovered the Americans and Australians tried numerous unsuccessful methods to smoke out the Viet Cong: trained German shepherd dogs, human
"tunnel rats," and crop-killing defoliates. The dogs and humans suffered appalling casualty rates and so many dogs were horribly mutilated by booby traps their handlers refused to allow them to be used.
At one point American troops brought in a well-trained squad of 3000 sniffer dogs, but the German Shepherds were too bulky to navigate the courses. One legend has it that the dogs were deterred by Vietnamese using American
soap to throw them off their scent, but more usually pepper and chilly spray was laid at entrances, often hidden in mounds disguised as molehills, to throw them off.
Large-scale American raiding operations used tanks, artillery and air raids, water was pumped through known tunnels, and, according to the Vietnamese, “engineers laid toxic gas.” The US used napalm and Agent Orange and turned
the land above the tunnels into a moonscape, Eventually the entire Cu Chi area was declared a free fire zone, where American soldiers had orders to kill anything that moved and planes dropped leftover bombs. An area covering
420 kilometers was pulverized with carpet bombs. Dubbed the "Land of Fire" in Vietnamese during the war, Cu Chi became "the most bombed, shelled, gassed, defoliated and generally devastated area in the history of warfare,"
wrote authors Tom Mangold and John Penycate.
Despite all this the Viet Cong hung on for a long time, even though only about 6,000 of the 16,000 guerrillas who lived in the tunnels survived the war. There were also thousands of civilian casualties as one might guess. One
American commander's report at the time said: "It's impossible to destroy the tunnels because they are too deep and extremely tortuous."