One of Asia's safest, most diverse habitats for rare and endangered species is a narrow, land mine–dense strip of jungle stuck between two industrial powerhouses with environmental records that are among the world's worst. The Korean Demilitarized Zone (DMZ) has, by accident, helped safeguard the Asiatic black bear, red-crowned crane, and black-faced spoonbill from extinction. Last September, South Korea asked the United Nations to recognize the DMZ's role in wildlife conservation by taking steps toward making part of it a World Heritage Site – getting the international community to protect and expand the wilderness area. "No other place in Korea resembles what it looked like before the war," says Lee Ki-sup, an ecologist from South Korea.

The DMZ, a 150-mile-long, 2.5-mile-wide stretch of land, has been a mandatory military-free zone since 1953 – and about 1 million active land mines, more than 2,500 a square mile, have ensured it remained so. Along with the endangered red-crowned cranes and vulnerable populations of black vultures and long-tailed gorals, there are about 1,100 plant species, 50 other mammals, and, some suspect, rare animals at the top of the food chain that have yet to be verified in the woods – like the Amur leopard and the ultimate Korean symbol of unity, strength, and perseverance: the tiger, widely believed to be extinct in the country for decades.

If the DMZ is an accidental animal preserve, then Lim Sun-nam may be seen as an unwitting wildlife biologist. A documentarian by profession, he stopped working in 1997 to investigate rumors that tigers were lurking in the DMZ. Lim, a stout 56-year-old, got permission from the government to enter the area on a quixotic one-man mission to find the beasts. He has since seen paw prints, chewed-up carcasses, and telltale markings on trees – but no actual tigers. He is one of the few people in the world who know which trails to take to avoid being blown up. (There are signs that it's common for even the animals to encounter mines.) During a hike inside the border with Lim, a mist hovers like a ghost in the valley, covering the verdant folds usually full of boars, pheasant, and deer. "Doesn't this look like an Asian safari park?" Lim asks.

Protecting the entire corridor in perpetuity hinges on cooperation with North Korea, says Dr. Choi Chung-il, the man in charge of South Korea's bid to the UN. But the country is perennially uncooperative, and the death of Kim Jong-il puts leadership further into question. In the future, if the Koreas reunite or if tension escalates, a World Heritage designation should at least keep the animals safe. There are enough land mines to keep cleanup crews busy – and poachers and developers out – for decades.