Complex sentence: The Korean Demilitarized Zone (DMZ;) is a strip of land running across the Korean Peninsula that serves as a buffer zone between North and South Korea which runs along the 38th parallel north.
Split into simpler sentences: The Korean Demilitarized Zone (DMZ;) is a strip of land running across the Korean Peninsula that serves as a buffer zone between North and South Korea. The DMZ is a "de-facto" border barrier, which runs along the 38th parallel north.