Per the Lonely Planet description, Vinh Moc is the remains of a coastal North Vietnamese village that went underground in response to unremitting American bombing. More than 90 families disappeared into three levels of tunnels running for almost 2 kilometers and continued to live and work while bombs rained down around them.
Our guide, Hua, is a 62 year old South Vietnamese veteran of the South Vietnamese Army during the two year war between North and South Vietnam after the US left in 1973.