Ho Chi Minh trail

The Ho Chi Minh Trail is a system of trails made in the Vietnam War send North Vietnamese soldiers into South Vietnam and to help the Viet Cong insurgents fight against non-communist South Vietnamese soldiers. Most of the trails were in Laos and Cambodia because the United States was not allowed to enter those countries to bomb the trails. Later in the war, the United States would secretly send US soldiers to fight communist Vietnamese soldiers in Laos and Cambodia.
In early 1971, South Vietnam–with United States support–tried to disrupt the Ho Chi Minh Trail by invading Laos and launching Operation Lam Son 719, but this operation was a failure.