The assassination of Austrian Archduke Franz Ferdinand on 28 June 1914 set off a chain of events that led to war in early August 1914.
The government was unable to deal with the economic crisis left by the war. ... The economic situation in Germany briefly improved between 1924-1929. However, Germany in the 1920s remained politically and economically unstable. The Weimar democracy could not withstand the disastrous Great Depression of 1929.
Post-war, all of the combatants were rather weighed down by large amounts of debt they had accumulated during the war. This, combined with rapid overproduction of currency, caused hyperinflation and doomed global economies, later leading to the Great Depression.