Starting as a stretch of barbed wire, and then a simple concrete-block wall, the Berlin Wall grew into a major fortified barrier. Between East and West Berlin, the Wall was actually two walls -- each 12 to 15 feet high, topped with a concrete tube to make climbing difficult. Those walls were made of concrete, with a mesh of reinforced steel inside -- making attempts to ram vehicles through the Wall virtually impossible.

On the East German side, the Wall was painted white, making would-be refugees easier to spot. On the West Berlin side, the Wall became a massive canvas for graffiti artists, including those expressing their contempt for the East's repressive measures.

A barrier also separated West Berlin from outlying parts of East Germany.