The Cu Chi Tunnels are 75 miles of interconnecting tunnels which were used by the Vietnamese army through the Vietnamese War (or American War because they connect with it). They served as hiding places and as routes for communication and provides. Quite a few troopers even lived in these tunnels https://arthurhktss.collectblogs.com/74999042/5-tips-about-sai-gon-list-you-can-use-today