Key point: The Korean DMZ is the world's most heavily armed border.
The recent defection of a North Korean soldier across the demilitarized zone (DMZ) that separates the two Koreas highlighted how difficult it is to cross from one Korea to the other. Fenced, mined and patrolled by soldiers from both sides, fortifications and large concentrations of combat-ready troops will make the Korean DMZ in the event of war the deadliest place on earth.
The current demarcation line between North and South Korea was settled by the Korean Armistice Agreement of July 1953. The two sides agreed on a demilitarized zone approximately 2.5 miles wide approximately 160 miles long, bisecting the peninsula. Technically there is no “border,” as neither Korea really considers the other Korea separate country, and so the DMZ has become the de facto border. Although the DMZ is commonly referred as following the thirty-eighth parallel line, it actually falls beneath the thirty-eighth parallel in the west and goes above it in the east.
North of the DMZ, the Korean People’s Army is responsible for the DMZ. (Although a Border Security Bureau exists, it protects only the borders with China and Russia.) North Korea has erected a series of fortifications and defensive structures designed to prevent South Korean forces from crossing the border. An electrified fence runs the length of the DMZ, along with minefields strewn with antipersonnel mines. The KPA has also built a number of towers designed to watch for South Korean incursions.