Attracted by the calm of long-abandoned machine gun posts, rare animals have been settling in the ruined bunkers that make up the Siegfried Line Hitler built to protect Germany's western border. Now wildlife groups are battling to stop authorities from bulldozing this giant legacy of the Nazi era.

The Siegfried Line, the 630-kilometer network of bunkers Hitler built in a vain attempt to protect his western frontier from an Allied invasion, is finally serving a purpose six decades after the end of World War II -- as a quiet haven for wild cats, bats and a host of other rare species.