The remilitarizaton of the Rhineland (German: Rheinlandbesetzung) began on 8 March 1936, when German military forces entered the Rhineland, which directly contravened the Treaty of Versailles and the Locarno Treaties. Neither France nor Britain was prepared for a military response, so they did not act. After 1939 commentators often said that a strong military move in 1936 might have ruined Hitler's expansionist plans. However, recent historiography agrees that both public and elite opinion in Britain and France strongly opposed a military intervention, and neither had an army prepared to move in.After the end of World War I, the Rhineland came under Allied occupation. Under the 1919 Treaty of Versailles, the German military was forbidden from all territories west of the Rhine or within 50 km east of it. The 1925 Locarno Treaties reaffirmed the permanently-demilitarized status of the Rhineland. In 1929, German Foreign Minister Gustav Stresemann negotiated the withdrawal of the Allied forces. The last soldiers left the Rhineland in June 1930.

After the Nazis took power in 1933, Germany began working towards rearmament and the remilitarization of the Rhineland. On 7 March 1936, using the Franco-Soviet Treaty of Mutual Assistance as a pretext, Chancellor and Fhrer Adolf Hitler ordered the Wehrmacht to march 20,000 German troops into the Rhineland, which caused joyous celebrations across Germany. The French and the British governments, unwilling to risk war, decided against enforcing the treaties.

The remilitarization changed the balance of power in Europe from France and its allies towards Germany by allowing Germany to pursue a policy of aggression in Western Europe that had been blocked by the demilitarized status of the Rhineland.

The fact that Britain and France did not intervene made Hitler believe that neither country would get in the way of Nazi foreign policy. That made him decide to quicken the pace of German preparations for war and the domination of Europe. On 14 March 1936, during a speech in Munich, Hitler stated, Neither threats nor warnings will prevent me from going my way. I follow the path assigned to me by Providence with the instinctive sureness of a sleepwalker".

Adolf Hitler (German: [ˈad.ɔlf ˈhɪt.lɐ] (listen); 20 April 1889 – 30 April 1945) was an Austrian-born German politician who was the dictator of Germany from 1933 until his death in 1945. He rose to power as the leader of the Nazi Party, becoming the chancellor in 1933 and then assuming the title of Führer und Reichskanzler in 1934. During his dictatorship, he initiated World War II in Europe by invading Poland on 1 September 1939. He was closely involved in military operations throughout the war and was central to the perpetration of the Holocaust, the genocide of about six million Jews and millions of other victims.

Hitler was born in Austria-Hungary and was raised near Linz. He lived in Vienna later in the first decade of the 1900s and moved to Germany in 1913. He was decorated during his service in the German Army in World War I. In 1919, he joined the German Workers' Party (DAP), the precursor of the Nazi Party, and was appointed leader of the Nazi Party in 1921. In 1923, he attempted to seize governmental power in a failed coup in Munich and was imprisoned with a sentence of five years. In jail, he dictated the first volume of his autobiography and political manifesto Mein Kampf ("My Struggle"). After his early release in 1924, Hitler gained popular support by attacking the Treaty of Versailles and promoting pan-Germanism, anti-Semitism and anti-communism with charismatic oratory and Nazi propaganda. He frequently denounced international capitalism and communism as part of a Jewish conspiracy.

By November 1932, the Nazi Party held the most seats in the German Reichstag, but did not have a majority. As a result, no party was able to form a majority parliamentary coalition in support of a candidate for chancellor. Former chancellor Franz von Papen and other conservative leaders persuaded President Paul von Hindenburg to appoint Hitler as chancellor on 30 January 1933. Shortly after, the Reichstag passed the Enabling Act of 1933 which began the process of transforming the Weimar Republic into Nazi Germany, a one-party dictatorship based on the totalitarian and autocratic ideology of Nazism. Hitler aimed to eliminate Jews from Germany and establish a New Order to counter what he saw as the injustice of the post-World War I international order dominated by Britain and France. His first six years in power resulted in rapid economic recovery from the Great Depression, the abrogation of restrictions imposed on Germany after World War I, and the annexation of territories inhabited by millions of ethnic Germans, which gave him significant popular support.

Hitler sought Lebensraum (lit. 'living space') for the German people in Eastern Europe, and his aggressive foreign policy is considered the primary cause of World War II in Europe. He directed large-scale rearmament and, on 1 September 1939, invaded Poland, resulting in Britain and France declaring war on Germany. In June 1941, Hitler ordered an invasion of the Soviet Union. By the end of 1941, German forces and the European Axis powers occupied most of Europe and North Africa. These gains were gradually reversed after 1941, and in 1945 the Allied armies defeated the German army. On 29 April 1945, he married his longtime lover, Eva Braun, in the Führerbunker in Berlin. Less than two days later, the couple committed suicide to avoid capture by the Soviet Red Army. Their corpses were burned.

Under Hitler's leadership and racially motivated ideology, the Nazi regime was responsible for the genocide of about six million Jews and millions of other victims whom he and his followers deemed Untermenschen (subhumans) or socially undesirable. Hitler and the Nazi regime were also responsible for the killing of an estimated 19.3 million civilians and prisoners of war. In addition, 28.7 million soldiers and civilians died as a result of military action in the European theatre. The number of civilians killed during World War II was unprecedented in warfare, and the casualties constitute the deadliest conflict in history.

Hitler's actions as Führer of Germany are almost universally regarded as gravely immoral. Prominent historian and biographer Ian Kershaw describes Hitler as "the embodiment of modern political evil", and that "never in history has such ruination—physical and moral—been associated with the name of one man".