How did the inter-German border, created in 1945, become one of the most formidable boundaries in the world by 1952? The early boundary was not fenced, but just years in the wake of National Socialism's “Thousand Year Reich” Germans on both sides broadly accepted and enforced it against other Germans. These early divisions made possible the GDR's physical closure and fortification of the border after 1952. The hastily drawn demarcation line between Allied zones of occupation had rather quickly expanded into a legal, economic, political, and social boundary—in which both East and West developed a stake.