On March 7, 1936, Adolf Hitler broke the Treaty of Versailles by sending troops into the Rhineland. From the article:verbatim
"Hitler reoccupies the Rhineland, violating the Treaty of Versailles
Nazi leader Adolf Hitler violates the Treaty of Versailles and the Locarno Pact by sending German military forces into the Rhineland, a demilitarized zone along the Rhine River in western Germany.
The Treaty of Versailles, signed in July 1919–eight months after the guns fell silent in World War I–called for stiff war reparation payments and other punishing peace terms for defeated Germany. Having been forced to sign the treaty, the German delegation to the peace conference indicated its attitude by breaking the ceremonial pen. As dictated by the Treaty of Versailles, Germany’s military forces were reduced to insignificance and the Rhineland was to be demilitarized.
In 1925, at the conclusion of a European peace conference held in Switzerland, the Locarno Pact was signed, reaffirming the national boundaries decided by the Treaty of Versailles and approving the German entry into the League of Nations. The so-called “spirit of Locarno” symbolized hopes for an era of European peace and goodwill, and by 1930 German Foreign Minister Gustav Stresemann had negotiated the removal of the last Allied troops in the demilitarized Rhineland.
However, just four years later, Adolf Hitler and the Nazi Party seized full power in Germany, promising vengeance against the Allied nations that had forced the Treaty of Versailles on the German people. In 1935, Hitler unilaterally canceled the military clauses of the treaty and in March 1936 denounced the Locarno Pact and began remilitarizing of the Rhineland. Two years later, Nazi Germany burst out of its territories, absorbing Austria and portions of Czechoslovakia. In 1939, Hitler invaded Poland, leading to the outbreak of World War II in Europe."