Descend into the Third Tunnel of Aggression, also known as the 3rd Infiltration Tunnel, discovered in 1978 just 52 km from Seoul. This 1,635-meter-long passage, 2 meters high and wide, was built by North Korea to stage a surprise invasion, capable of moving 30,000 troops per hour. Its coal-dusted walls, exposed by a defector's tip, reveal the failed plot. Walk its eerie depths with your private guide, who tailors the history to your interests, making this third tunnel tour feel like a spy thriller. If confined spaces aren't for you, wait at the exit. A gripping highlight of your private DMZ tour from Seoul, this stop unveils the Korean Demilitarized Zone's secrets.