World War I reparations
As a "quiet fight" in the Ruhr, the German government began the hyperinflation that destroyed the German economy in 1923. In 2008, a British historain Richard J. Evans said that the German government was responsible for the hyperinflation as they preferred this to paying reparations.  The Germans won the world's pity, and after that, the French were forced to agree to the Dawes Plan of April 1924, which lowered the reparations.  Under this new plan, Germany paid 1 billion marks in 1924 and reached the total of 2.25 billion by 1927. After that year, Germany was able to pay 2.5 billion marks per year. However, the Germans still stop paying the reparations. To deal with this, the Allies met in a conference in London in July-August 1924, and was the first time that Germany challenged the Versailles Treaty.