Germany's beating in World War One made political, economic and social fall in the Weimar Republic and led to the rise of the National Socialist German Workers' Party (NSDAP) or Nazi party.
The First World War put stress on the German people. The space between the rich and poor got bigger and also between classes. It had direct effect on the workers as wages dropped and the amount of food went down. Food was sold on the black market but the prices were high and the poor could not afford to buy it. This led to as many as 700,000 deaths because of hypothermia and starvation in the winter of 1916-17.
In order to get the German people to allow the fatigue of the war, chancellor Bethmann Hollweg promised political rebuild in a speech on February 1917. This promise led to a political crisis and sent 400, 000 ammunition workers in Berlin on strike, this threatened to do enormous amounts of harm to the arms production. However, as long as the military held their powerful position and the chance for a the win of the war remained, they didn't seem to worried about it. After the chancellor was forced to resign in July 1917 military fixation got bigger. In September 1918 the military effort suddenly fell apart. The allied powers, in particular President Wilson of the United States, made Germany become a democracy. On November 1918 the they announced the breakthrough of the birth of the new Weimar Republic.
On June 28 1919 the German government signed the Treaty of Versailles demanded by the allied powers.