Every day, thousands of people flock to the DMZ from Seoul to gain a glimpse of ... The 3rd Infiltration Tunnel is one of four known tunnels under the border of North and South Korea.

From Gyeonggi-do in the west to Gangwon-do in the east, the 160-mile (258km) long Demilitarised Zone (DMZ) divides the Korean ... entry to the infiltration tunnels once dug by the North Koreans.