The once frightening and desolate border that separated western Europe from the Communist countries is taking on a new role. The Iron Curtain is now a 5,000-mile network of bicycle paths that go past guard towers, barbed wire fences and other historical landmarks from the Cold War.The once frightening and desolate border that separated western Europe from the Communist countries is taking on a new role. The Iron Curtain is now a 5,000-mile network of bicycle paths that go past guard towers, barbed wire fences and other historical landmarks from the Cold War.