Pictured at the bottom is a photograph of a model displayed at the beginning stage of our tour. It shows a cross-sectional view of the tunnel design and probably the best way to get an idea of the design, but also where we crawled later on. The 1st level is completely functional; sleeping, eating, cooking and food storage and the second two are involved with war movements. They go as deep as 10-12 meters below the ground, taking (if my memory serves me correctly) 25 years to construct out of the perfectly hard, clay soils here in Vietnam. These tunnels stretch all the way to the Cambodian boarder, as a means to collect resources whilst within the war. Absolutely amazing!