In 1936, Adolf Hitler violated the Treaty of Versailles by reoccupying the Rhineland. The Treaty of Versailles, which ended World War I in 1919, had demilitarized the Rhineland and forbade German troops from being stationed there to reduce the threat of future aggression against France.
On March 7, 1936, Hitler ordered German troops to march into the Rhineland, defying the treaty and the Locarno Treaties, which guaranteed the borders and demilitarization of the area. This move was a significant step in Hitler's expansionist policies and emboldened him to pursue further aggressive actions leading up to World War II.