After the second world war, Germany was divided into east and west. Between the two, the communist masters of East Germany erected an imposing barrier along the 870 border to keep people both in and out. But rather being a single fence or wall, the barrier was also a wide strip outfitted with minefields, bunkers, watch towers, and sand pits. Now that Germany has been reunited, this strip of land running 870 miles along the old border is a long, continuous, undeveloped property. In the end, the Soviets had not built a barrier, but a nature preserve.