- The tunnels of Cu Chi are an immense network of connecting underground tunnels located in the Cu Chi district of Vietnam, and are part of a much larger network of tunnels that underlie much of the country. The Cu Chi tunnels were the location of several military campaigns during the Vietnam War, and were the National Front for the Liberation of South Vietnam's base of operations for the TET Offensive in 1968. 

- The tunnels were used by NLF guerrillas as hiding spots during combat, as well as serving as communication and supply routes, hospitals, food and weapon caches and living quarters for numerous guerrilla fighters. The role of the tunnel systems should not be underestimated in its importance to the NLF in resisting American operations and protracting the war, eventually persuading the weary Americans into withdrawal.