The Korean demilitarized zone (DMZ) is one of the last remnants of the Cold War. The strip, 150 miles (250 kilometers) long and 2.5 miles (four kilometers) wide, separates North and South Korea and is one of the most heavily guarded areas in the world. It’s estimated that some two million land mines are buried there, and border guards peer at one another across the strip day and night. At Panmunjom, there are hundred-meter-tall flagpoles flying the flags of both nations, and loudspeakers spit out propaganda 20 hours a day. DMZ: Memories of No Man’s Land uses virtual reality to explore this strip of land, which ordinary citizens aren’t permitted to enter. You can zoom in on guard towers, the barracks where the neighboring nations have been locked in ineffectual negotiations since the ceasefire of 1953, and the muddy paths where soldiers go on risky nocturnal patrols. Korean government officials talk about the origins and history of the zone. In letters, military personnel report on their tours of duty on the border. The paranoia and constant sense of threat are almost palpable, but curiosity drives us to push ever deeper into this impenetrable piece of no man’s land.