WW1 left Germany in a very poor state economically, providing an excellent setting for Nazism, specifically the Fascist ideaology's blaming of the ethnic peoples of Germany for Germany's downfall. The bitter sense of resentment at Germany's misery was very easily turned around into German nationalism, too, which provided the drive behind the movement.
Answer
OD?
INflation was bad but this action helped the collapse
The building of the Berlin Wall was for namely preventing the exodus of East Germans from East to West Berlin then to West Germany.