I saw mention of this topic in Richard Russell's newsletter recently. The Demilitarized Zone that seperates North and South Korea is something of a treacherous no-man's-land, dotted with land mines and fenced in with barbed wire. But the largely uninhabited boundry within has become something of a nature preserve. From "War and Wildlife", by reporter Michael Casey:
Hundreds of bird species winter here, among them at least two endangered types of crane — white-naped and red-crowned. Fifty types of mammals live here, including the rare Asiatic black bear, Amur leopard and, some believe, the Siberian tiger, based on traces of footprints and droppings. More than 1,000 different plant species thrive.
Now the worry is that an eventual peace will bring about the end of a DMZ, and development will be introduced where nature now flourishes. Interesting.