The Cu Chi tunnels are located in Tay Ninh province next to the Saigon River, about half-way between Ho Chi Minh City and the Cao Dai Holy See – the journey usually takes around 1½ hrs from either end, depending on the traffic.

The original tunnels were dug long ago by the Viet Minh to provide hiding places from which to attack French soldiers. During the 1960s, the Viet Cong reopened them and greatly extended them both horizontally and vertically. At their peak, an integrated 200km network of passages, on five or more levels in places, stretched to within thirty kilometres of the centre of Saigon. Their total length was somewhere between 200km and 300km, and the deepest levels were more than 30m underground. The complex included entire underground ‘villages’ – accommodation, canteens, and even schools and hospitals.

The tunnel entrances, exits, ventilation pipes, chimneys, and waste channels were all ingeniously camouflaged and guarded by an array of vicious booby traps designed to maim intruders (there are many examples in the War Remnants Museum). Blast screens and water traps protected inhabitants from grenades and gas, and the passages could be quickly sealed off to prevent flooding.