The Treaty of Versailles officially ended World War I. The terms of the Treaty of Versailles not only had serious repercussions for the German economy, but also generated a lot of resentment within Germany over the oppressive terms of their defeat. Some Austrians were pretty resentful too, in particular a young man named Adolf Hitler who'd served in the German army during the conflict. The Treaty of Versailles left Germany bankrupt, disarmed, humiliated, and pretty ripe for someone like Hitler to come to power within 20 years.
Talk about a day that will live in infamy…The German Workers Party officially changed its name to the Nationalsozialistische Deutsche Arbeiterpartei: the National Socialists German Workers' Party. One of its most enthusiastic members was Adolf Hitler.
Hitler ramped up fundraising and propaganda for the Party, even establishing a newspaper to spread their philosophy of German nationalism, Aryan supremacy, and anti-Semitism (source).
The American economy had grown rapidly through the 1920s, based largely on speculative investments and minimal regulation. As a result, the stock market crashed suddenly and aggressively, sending the U.S. into dire financial straits. Many other countries and their colonies were affected because of economic relationships established after World War I, including Germany and Japan (source).
The economic situation of both those countries would become motivation for invading others, albeit for different reasons.
The Nazi Party hadn't had a major presence within the German government until the 1930 election. They won 18.3% of the votes, making them the second largest party represented in the German government (source).
After the 1932 election, the Nazi party held 37% of all the seats in the Reichstag (source). The March 1933 election got them 44% of the vote. The rise in power was partly due to massive propaganda campaigns and the use of violence by street soldiers for the Nazis known as "brownshirts," the paramilitary wing of the party.
Once the Nazis got 44% of the vote, they almost immediately passed an act that allowed Hitler and his government to issue laws independent of the president (yes, there was still a president) and the Reichstag. Basically, they voted to give Hitler dictatorial power (source).
When longtime president Paul von Hindenburg ran for election in 1932, he only did it to prevent Hitler from getting the job. He was 84 at the time. However, he also didn't want to ignore Hitler's popularity at the time, so he made him second-in-command. Hitler used this position to take dictatorial power and become the "Führer."
As soon as Hitler became chancellor and the Nazis had serious power in the Reichstag, they started passing laws preventing Jews from having a number of different type of jobs, limiting Jewish attendance at universities, and enacting boycotts of Jewish businesses.
Once the only politician keeping Hitler slightly in check died, Hitler used the opportunity to become Führer, chancellor, and commander in chief of the army, while keeping his position as head of the Nazi Party. Membership in the party soon became mandatory for civil servants and government bureaucrats. His power became total, and the Nazis took control not only of the government, but the social and cultural realms of German life as well (source).
The Nuremburg Law defined a Jew by their family lineage (3 out of 4 grandparents). It also forbade marriage between Jews and non-Jews, and revoked German citizenship for Jews.
The two Fascist states had been buddies for years before the war. The Rome-Berlin Axis was the first major step towards that alliance, which was solidified by the Pact of Steel in 1939.
Germany and Japan signed this pact to protect each other from the Soviet Union, taking another big step towards solidifying the Axis powers. Italy would sign on in 1937.
Hitler's early invasions were focused on taking over territory with significant German populations. Austria had its own branch of the Nazi Party, which had gained a lot of power in recent years. Hitler used his influence to bully the Austrian government into not resisting the invasion, and when the German army invaded, they were greeted with relative enthusiasm by the Austrian people (source). Well, except for Captain Georg von Trapp.
The United States took an isolationist stance in the 1930s, put into law in a series of Neutrality Acts, which prevented the U.S. from taking sides in foreign conflicts. Reeling from the Great Depression and remembering the carnage of World War I, many Americans wanted to avoid getting tangled up in world affairs again. FDR tried to weaken the acts later when he read the handwriting on the European wall (source).
In 1938, Great Britain became seriously concerned about the situation between Germany and Czechoslovakia. The area of Czechoslovakia known as the Sudetenland was populated largely by German-speaking peoples, and Hitler had been vocal about wanting to protect those people from oppression under the Czech government. Britain and France thought that Hitler might very well invade Czechoslovakia to get his hands on the Sudetenland, although at the time Hitler was not planning an invasion.
Churchill's predecessor Neville Chamberlain eventually negotiated the Munich Pact, in which Germany got the Sudetenland in exchange for, well, not invading Czechoslovakia. In case you were wondering, Czechoslovakia was not included in these negotiations. Chamberlain came back to Britain a hero, cheered by the public for maintaining the peace.
In a move that surprised everyone, Hitler made a deal with the Soviet Union that would allow Germany to invade Poland without fear of retaliation from Russia. Hitler envisioned German control of all of Eastern Europe, and wanted to get as much done as possible before the western countries could retaliate. He promised the Soviets the eastern two-thirds of Poland in exchange for letting Germany invade.
The German invasion of Poland is generally regarded as the start of World War II. It was the last straw for the countries of Western Europe, who quickly and formally declared war on Germany as a result. As a pretext for the invasion, German soldiers dressed up as Poles attacked the radio station in the German border town of Gleiwitz, running around shooting randomly and broadcasting in Polish. They left behind bodies of dead "Poles," who were actually concentration camp inmates killed by lethal injection and then shot (source). This "provocation" was used to justify the invasion.
As soon as Hitler invaded Poland, the people and government of Great Britain could see that the policy of appeasement had failed. Britain issued Hitler an ultimatum, but didn't get a response. After a short debate in Parliament, war was formally declared (source). France's declaration followed soon after.
Winston Churchill had foreseen the invasion of Norway, and Great Britain was about to start laying mines there to stop the Germans. The process was supposed to begin on April 8, but debates with the Norwegian government delayed things and distracted them while the Germans invaded.
Hitler surprised the western Allied powers when he invaded the Netherlands as the start to his major western offensive. From here he'd go on to invade Belgium, Luxembourg, and France. Neville Chamberlain had already been heavily criticized for his lack of action after the German invasion of Norway, and on the same day that Britain learned of the invasion of The Netherlands, Chamberlain resigned and Churchill was named Prime Minister.
Having been made Prime Minister a few days earlier, and having assembled his new cabinet to deal with the war, Churchill finally got up in front of his frenemies in Parliament to get them fired up and ready to fight the Nazis.
Towards the end of Germany's aggressive invasion of western Europe, it wasn't going well for Britain and the Allied powers. The allied forces, fighting the Battle of France, found themselves backed onto the beaches in northern France, surrounded by the German army. Their only way to escape was the port of Dunkirk.
What followed was one of the most epic rescues in history, which you can read about in detail here. You'll also be able to watch it on the big screen. Basically every fisherman and boat owner on the British coast sailed across the English Channel to Dunkirk and helped evacuate the soldiers back to Britain, risking their own lives in the process.
People were shocked at how quickly France was defeated by the Nazis. It was a dark time for Britain in the war, when things looked pretty bleak or even hopeless for Hitler's opponents—which at this point was basically Great Britain (source).
Once France fell, Britain was the next big prize. When the Brits didn't surrender in fear after the French occupation, Hitler turned to his air force. However, they really weren't well-prepared for what turned out to be the first all-air battle in military history. The Royal Air Fore defeated the Luftwaffe soundly enough to convince Hitler to postpone any further invasion. Civilization saved.
The Luftwaffe bombed Britain repeatedly over 8 months, focusing especially on the London area. 43,000 civilians died in the bombings, which ended when Hitler turned his attention to his planned invasion of the U.S.S.R. (source). The royal family endeared themselves to their subjects by remaining in London during the blitz.
Churchill breathed a sigh of relief. Hitler, bound by the terms of the Anti-Cominterm Pact with Japan, declared war on the U.S. Bring it on, said FDR.
The Holocaust, Normandy, and Hitler's suicide
Hitler's disastrous decision to invade the U.S.S.R. in 1941 got him stranded in Russia in the winter. The tide began to turn in favor of the Allies, but Hitler continued to wreak havoc and began his "final solution" of the "Jewish problem" in Europe. The problem was there were Jews in Europe. The solution was to deport the Jews in Germany and its occupied countries to extermination camps in the hopes of making all of Europe judenfrei: Jew-free. As late as May, 1944, Hitler was rounding up Jews and deporting them to Auschwitz and other camps.
On June 6, 1944, American forces, under the command of Supreme Allied Commander General Dwight D. Eisenhower, landed in Normandy and began driving back German forces across Europe.
On April 30, 1945, Hitler committed suicide as the Red Army entered berlin. German surrendered a week later.
Here's some of what he said:
The German war is therefore at an end. After years of intense preparation, Germany hurled herself on Poland at the beginning of September, 1939; and, in pursuance of our guarantee to Poland and in agreement with the French Republic, Great Britain, the British Empire and Commonwealth of Nations, declared war upon this foul aggression. After gallant France had been struck down we, from this Island and from our united Empire, maintained the struggle single-handed for a whole year until we were joined by the military might of Soviet Russia, and later by the overwhelming power and resources of the United States of America.
Finally almost the whole world was combined against the evil-doers, who are now prostrate before us. Our gratitude to our splendid Allies goes forth from all our hearts in this Island and throughout the British Empire. […] Advance, Britannia! Long live the cause of freedom! God save the King! (Source)