The JSA is the site of the signing of the armistice and the chosen location for most negotiations between North and South Korea. It lies on the border just north of Seoul in the small village of Panmunjom. On the western edge runs the Sachon River, spanned by the Bridge of No Return, the only way across the Sa Chon until the incident forced the North Koreans to build a new bridge, which they did in just 72 hours. The Bridge of No Return is bisected by the Military Demarcation Line (MDL). Not surprisingly, the JSA is dotted with checkpoints and guard posts to keep tabs on the opposition, including one on each end of the bridge.