The bridge of no return crosses the military demarcation line between North Korea and South Korea, it was used for prisoner exchanges at the end of the Korean armistice in 1953. The bridge was actively used by the North Koreans until the “Korean axe murder incident” (what?) in August 1976.
The military demarcation line runs through the middle of the bridge. At the end of either side of the bridge are guard houses of the respective countries. The North Korean building is called KPA#4 while the United Nations Command checkpoint was called CP#3, which was abandoned in the mid-1980s. The North Korean Army had made numerous attempts to grab UNC personnel from the old CP#3 and drag them across the bridge into North Korean territory.
Because of this proximity to North Korean territory, being surrounded on all access routes by North Korean checkpoints, and repeated attempts to kidnap the UNC personnel working there, CP#3 is often referred to as "The Loneliest Outpost in the World".