An underground war was actively pursued in the Afghan War. Water pipes extend under the entire Afghan territory. In wartime, Afghans have used these tunnels to hide and also to appear suddenly in the enemies rear. To clear these tunnels, Soviet troops used explosives and gasoline. The most famous underground base of the Mujahideen and then the Taliban was Tora Bora – this tunnel system went to a depth of 400 meters and had a length of . To combat guerillas in tunnels both the Soviet Union and the United States have created special forces.