Germany was able to overcome the French line of defense, known as the Maginot Line, by simply invading Belgium first and marching its troops into France through Belgium. The French overreliance on the Maginot Line contributed to its rapid surrender in the first few weeks of the Second World War.

The Battle of Britain was a prolonged campaign by the German Luftwaffe (Air Force) to bomb Britain into submission. The battle was primarily fought in the air between the Luftwaffe and the Royal Air Force. 

Neville Chamberlain was Prime Minister of Britain from 1937 to 1940. He supported and encouraged other countries to sign the Munich Agreement, which allowed Germany to annex the Sudetenland (a region of Czechoslovakia with many ethnic-German inhabitants). This policy of "appeasement"—letting Hitler have some territory in the hope that this would quell his ambitious aggression—is generally considered a massive failure considering what was to follow, but at the time, Chamberlain was celebrated as a visionary hero.

In the early years of World War Two, Roosevelt and the American government maintained an official policy of neutrality. However, unoficially Roosevelt was firmly on the side of Churchill and the British. The Lend-Lease Act of 1941 was a way to provide war supplies to the British despite Britain's lack of credit. It was a precursor to direct American involvement in the conflict. 

The Battle of Britain was fought in the summer and autumn of 1940, shortly after Nazi Germany occupied France. The Battle was fought in the skies above Britain and the English Channel between the German Luftwaffe (air force) and the Royal Air Force of Britain. The Germans hoped to achieve aerial supremacy over the British in preparation for a later land invasion of the island. However, they eventually resorted to trying to terror bomb the British public into submission. The Battle ended in victory, at enormous cost, for the British. But, it also filled the British public with a resolve that would prove enormously important throughout the rest of the war, as for a time Britain stood alone against Nazi Germany in Europe. 

The Maginot Line was a series of defensive fortifications established by the French on their borders with Germany and Switzerland. The French experience of World War One taught them that solid and well-established defensive fortifications would be vital to protecting France in any future European conflict. The French established the Maginot Line to discourage or prevent German attacks on France.

Erwin Rommel, usually referred to as just Rommel or the "Desert Fox," was a German military leader during the Second World War. He became famous among the Allied powers for his brilliant leadership and diplomatic decorum. He was a war hero to Nazi Germany, but he also loathed Hitler, and when his loathing became public knowledge, he was pressured to commit suicide by the German high command on pain of having his family executed and took his own life.

The Nuremberg Laws were established in 1935 by the German Nazi Party. The laws declared that all Jews in Germany were no longer German citizens and deprived Jews of certain human rights. It was not until the so-called "Final Solution" that the systematic execution of Jews began.

In 1939, the Germans and the Soviet Union signed a nonagression pact promising that they would not attack each other during the Second World War. The secret treaty was effective for a time but was ended by Hitler's planned invasion of Russian territory. 

In 1923 Hitler was a well-known and charismatic political speaker in Germany, but he was not yet the powerful leader that popular history remembers. He attempted to organize an overthrow of the German government by the Nazi Party, but he misjudged the moment and the revloution was a spectacular failure. Hitler was tried and imprisoned, but the momentum for his cause continued to build as many millions of Germans began to sympathize with Hitler. He spent his time in prison writing Mien Kempf which clearly outlines his horrifying philosophy.