Standing on top of a small mountain, Kim Seung-ho gazes out over an expanse of paddy fields glowing in their autumn gold, the ripening grains swaying gently in the wind. In the distance, North Korea stretches beyond the horizon.

“It’s so peaceful,” says the director of the DMZ Ecology Research Institute. “Over there, it used to be an artillery range, but since they stopped firing, the nature has become so beautiful.”

The land before him is the demilitarised zone, or DMZ, a strip of land that runs across the Korean peninsula, dividing North and South Korea roughly along the 38th parallel north. Stretching 155 miles (250km) across the peninsula and 2.4 miles wide, the DMZ remains one of the world’s most heavily fortified borders, strewn with landmines and flanked by military installations on both sides.

Yet, in the 72 years since the war ended, this forbidden strip has become an accidental ecological paradise.

The zone’s varied terrain creates distinct habitats: the wetlands of the western sector shelter migrating cranes, while the rugged eastern mountains provide sanctuary for some of the country’s most threatened mammals, including Siberian musk deer and Asiatic black bears.

South Korea’s National Institute of Ecology has documented nearly 6,000 species here, including more than 100 endangered species – representing more than a third of South Korea’s threatened wildlife.