French and Belgian troops marched into the Ruhr region of Germany, sparking a tense standoff between the former World War I allies. The occupation was a drastic measure to force Germany to make good on its outstanding war reparations, which had been delayed and renegotiated multiple times since the Treaty of Versailles. As the industrial heartland of Germany, the Ruhr region was crucial to the country's economy, and the occupation was a bold move to bring Germany back in line. The move would have far-reaching consequences, exacerbating German resentment and contributing to the rise of extremist groups in the tumultuous 1920s.