The Wehrmacht:

The Wehrmacht was founded by Hitler in 1935 in Germany. The Wehrmacht was the armed forces of the Third Reich. The three big branches of the Wehrmacht were the Heer, the Luftwaffe, and the Kriegsmarine.The Heer was the Army of the Wehrmacht, the Luftwaffe was the Air Force of the Wehrmacht, and the Kriegsmarine was the Navy of the Wehrmacht. 

Wilhelm Keitel was head of the Heer, Hermann Göring was head of the Luftwaffe and Wehrmacht, and Karl Dönitz was head of the Kriegsmarine. When Hitler rose to power as chancellor in 1933, he started to create German military aviation. When Paul Von Hindenburg died on August 2, 1934. Hitler became commander of the German Armed Forces.

After Germany occupied Poland in 1939, the Allies had declared Germany but nothing was done by either one of the nations on the Western Front until 1940, when Germany took the Benelux in order to avoid the Maginot Line, a wall of defenses on the French-German border, but it wasn't on the Belgian border, which was a major flaw in the development of the Maginot Line.

With the war on the Eastern Front commencing on June 22, 1941, the Wehrmacht had some modifications, the SS took full control of the Wehrmacht, along with all of the other divisions listed above. The Panzer Divison was taken over by the SS as well. By 1942, there was little to no activity on the Western Front from the Allies.

By 1942, the Eastern Front had reached a stalemate when the Russian winters had arrived. The situation was then in the Soviets' favor. Adolf Hitler pushed the Wehrmacht commanders, along with Göring to continue the fight on the Eastern Front. Then things took a turn for the worst on the Nazi and Soviet Fronts. 

The Nazis were not stopping the fight on the Eastern Front, which meant for the Soviets that they wouldn't be able to finish the war. On the Nazis' side, the harsh winters meant that the vehicles' oil froze up, which forced them to stop continuing the war. Dumbfounded, Hitler was desperate to finish the war, and forced the Wehrmacht to continue.

By 1944, the Nazis were losing on the Eastern Front, as well as on the Western front, with the Battle of Normandy being a failed battle, then the Wehrmacht started to collapse. By 1945, the Wehrmacht has officially failed to defend Berlin, despite all of the technological advancements created by the Nazis. Such as the Me (Messerschmitt) 262, history's first official fighter jet.

Wilhelm Keitel:

Wilhelm Keitel was born on September 22, 1882, in Germany. Keitel served during World War I and held posts under the Weimar Republic from 1918 - 1933. In 1935 Keitel was appointed chief of staff of the Wehrmachtamt, the Armed Forces Office. Then in 1938, Keitel was appointed Oberkommando der Wehrmacht, Armed Forces High Command. He was the head of the Armed Forces High Command until the end of World War II.

He had a vital role in Hitler's Germany. He ordered the French surrender in June 1940.  In June, Hitler's Field Headquarters was bombed when Keitel was there. He was not injured at all. 

After the Nazis surrendered on May 7, 1945, a lot of the Generals were still out there and had to pay for the crimes they committed. After World War II, Keitel was convicted of war crimes, crimes against humanity, and waging a war of aggression. Keitel refused to be executed by a firing squad. So he was hanged in Nuremberg on October 16, 1946.