The Soviet Union and the Eastern bloc states had strongly isolationist policies and they developed complex systems and infrastructure to restrict their citizens travel beyond the Iron Curtain.[23] About 3.5 million people left the GDR for West Germany before the building of the Berlin Wall and the Inner German border in August 1961. After that it was still possible to leave legally, by applying for an Ausreiseantrag [de] (permission to leave). Between 1961 and 1988 about 383,000 people left this way.[24][Note 1]