During the Cold War, it was difficult for West Germans to visit East German relatives and friends and impossible vice versa. For East Germans, especially after the building of the Berlin Wall on 13 August 1961 and until Hungary opened up its border to the West in the late 1980s, thus allowing hundreds of thousands of vacationing East Germans to flee into Western Europe, it was only possible to get to West Germany by illegally fleeing across heavily fortified and guarded border areas.