page_title: Củ Chi tunnels
section_title: U.S. campaigns against tunnels
hierarchical_section_title: Củ Chi tunnels / U.S. campaigns against tunnels
caption_attribution_description: English: A closed trap door leading into the Cu Chi Tunnels in Vietnam. Completely camouflaged, the trap door is invisible.
context_page_description: The tunnels of Củ Chi are an immense network of connecting tunnels located in the Củ Chi District of Ho Chi Minh City, Vietnam, and are part of a much larger network of tunnels that underlie much of the country. The Củ Chi tunnels were the location of several military campaigns during the Vietnam War, and were the Viet Cong's base of operations for the Tết Offensive in 1968.
  The tunnels were used by Viet Cong soldiers as hiding spots during combat, as well as serving as communication and supply routes, hospitals, food and weapon caches and living quarters for numerous North Vietnamese fighters. The tunnel systems were of great importance to the Viet Cong in their resistance to American forces, and helped to counter the growing American military effort.
context_section_description: The tunnels of Củ Chi were noticed by U.S. officials, who recognized the advantages that the Viet Cong held with the tunnels and so launched several major campaigns to search out and destroy the tunnel system. Among the most important were Operation Crimp and Operation Cedar Falls.
  Operation Crimp began on January 7, 1966, with B-52 bombers dropping 30-ton loads of high explosive onto the region of Củ Chi, effectively turning the once lush jungle into a pockmarked moonscape. Eight thousand troops from the U.S. 1st Infantry Division, 173rd Airborne Brigade Combat Team, and the 1st Battalion, Royal Australian Regiment combed the region looking for any clues of PLAF activity.
  The operation did not bring about the desired success. For instance, when troops found a tunnel, they would often underestimate its size. No one was usually sent in to search the tunnels, as it was so hazardous. The tunnels were often rigged with explosive booby traps or punji stick pits. The two most common responses in dealing with a tunnel opening would be to flush the entrance with gas, water or hot tar to force the Viet Cong soldiers into the open or to toss a few grenades down the hole and "crimp" off the opening. Those approaches proved ineffective because of the design of the tunnels and the strategic use of trap doors and air filtration systems.
  However, an Australian specialist engineering troop, 3 Field Troop, under the command of Captain Alexander "Sandy" MacGregor ventured into the tunnels, which they searched exhaustively for four days, l and found ammunition, radio equipment, medical supplies, food, and signs of considerable Viet Cong presence. One of their number, Corporal Robert "Bob" Bowtell, died when he became trapped in a tunnel that turned out to  be a dead end. However the Australians pressed on and revealed for the first time the immense military significance of the tunnels.  At an international press conference in Saigon shortly after Operation Crimp, MacGregor referred to his men as "tunnel ferrets. " An American journalist who had never heard of ferrets, used the term "tunnel rat," and it stuck. After his troop's discoveries in Củ Chi, MacGregor was awarded a Military Cross.
  From its mistakes and the Australians' discoveries, U.S. command realized that it needed a new way to approach the dilemma of the tunnels. A general order was issued by General Williamson, the Allied Forces Commander in South Vietnam, to all Allied forces that tunnels had to be properly searched whenever they were discovered. It began training an elite group of volunteers in the art of tunnel warfare, armed only with a handgun, a knife, a flashlight, and a piece of string. The specialists, commonly known as "tunnel rats", would enter a tunnel by themselves and travel inch-by-inch cautiously looking ahead for booby traps or cornered PLAF. There was no real doctrine for the approach, and despite some very hard work in some sectors of the Army and the Military Assistance Command, Vietnam, to provide some sort of training and resources, it was primarily a new approach that the units trained, equipped, and planned for themselves.
  Despite the revamped effort at fighting the enemy on their own terms, U.S. operations remained insufficient at eliminating the tunnels completely. In 1967, General William Westmoreland tried to launch a larger assault on Củ Chi and the Iron Triangle. Called Operation Cedar Falls, it was similar to the previous Operation Crimp but was on a larger scale with 30,000 troops, instead of 8,000. On January 18, tunnel rats from the 1st BN 5th Infantry Regiment of the 25th Infantry Division uncovered the Viet Cong district headquarters of Củ Chi, containing half a million documents concerning all types of military strategy. Among the documents were maps of U.S. bases, detailed accounts of PLAF movement from Cambodia into Vietnam, lists of political sympathizers, and even plans for a failed assassination attempt on Robert McNamara.
  By 1969, B-52s were freed from bombing North Vietnam and started "carpet bombing" Củ Chi and the rest of the Iron 
caption: A trap door on the jungle floor leads down into the Củ Chi tunnels. Closed and camouflaged, it is almost undetectable.
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