The Third Tunnel

This guide to the Third Tunnel near the DMZ starts in 1975, when a North Korean defector named Kim Bu-seong told South Korean intelligence that the North was digging under the border toward Seoul. It follows the years of searching that came after, soldiers driving water-filled pipes into the ground along the suspected path and waiting for a blast to give the tunnel away. It also covers North Korea's cover story once the passage was found, and the black smears on the granite meant to sell it. Look closely at the rock walls around you as you go.