Địa Đạo Củ Chi

This guide to the Cu Chi tunnels near Ho Chi Minh City follows the American soldiers sent crawling into these passages during the Vietnam War, and how an Australian engineer's nickname for them got garbled by a reporter into tunnel rat. It traces the network's growth from hand-dug resistance tunnels in the late 1940s into a full underground world of kitchens, hospitals and meeting halls by the 1960s, and this site's role as a secret headquarters from 1968 until the war's end. Soldiers called the pitch-black world underground the black echo.