Definition of Bundesautobahn 9

It served as one of three transit autobahns toward West Berlin during the Cold War. Between 1945 and 1966 the A9 was interrupted at the border between Bavaria and Thuringia (the then inner-German border) since the bridge over the river Saale was destroyed near the end of World War II. Traffic to and from West Berlin was diverted via A 72 (until 1951) and B 2 (from 1951 until 1966).