The excavations were used mostly for communication between villages and to evade French army sweeps of the area.
There were even theaters inside the tunnels where performers entertained with song and dance and traditional stories.
But life in the tunnels was difficult.
Almost everyone had intestinal parasites of significance.
Only about 6,000 of the 16,000 cadres who fought in the tunnels survived the war.
Large scale ground operations involving tens of thousands of troops were launched.
They ravaged rice paddies, bulldozed huge swathes of jungle, and villages were evacuated and razed.
The Viet Cong guerrillas remained safe and sound inside their tunnels.
The job of a tunnel rat was fraught with immense dangers.
The entrance holes in the ground were barely wide enough for the shoulders.
The tunnel rats, who were often involved in underground fire fights, sustained appallingly high casualty rates.
Captured US uniforms were put out to confuse the dogs further.
Most importantly, the dogs were not able to spot booby traps.
So many dogs were killed or maimed that their horrified handlers then refused to send them into the tunnels.
The gesture was militarily useless by then because the USA was already on its way out of the war.
The tunnels had served their purpose.
