Located some 40 kilometres northwest of Ho Chi Minh City (formerly known as Saigon), the Cu Chi tunnels are an impressively large network of underground tunnels connected to each other. These tunnels were once used by the local guerrillas as their means of moving around and hiding during the Vietnam War. The Cu Chi Tunnels were also once an important element of the 1968 Tet Offensive, during which the Viet Cong used the tunnel network as a base of operations. At present, the tunnels are a popular tourist attraction, where visitors are allowed to explore the relatively safer parts of the Cu Chi Tunnels.