In 1933 Adolf Hitler took over Germany as Führer and the Third Reich ended. In 1938 Austria was annexed. In 1939 Germany took control of the Czech Republic and established a puppet state in Slovakia. After this due to threats from Britain and France and the implied threat of American military action Adolf Hitler consolidated his earnings and did not proceed further. However, the Slovak Republic was invaded and transformed into the Slovak Socialist Republic by the Soviet Union in 1943 despite German objections. Adolf Hitler died in 1948 of a heart attack and was succeeded by Karl Dönitz.
During Hitler's rule "undesireables" were sent to concentration camps. These included political prisoners, Jews, Gypsies, homosexuals, and the mentally ill. The Holocaust would've likely taken out millions of people, possibly up to 12 million or higher if Hitler had taken over more land in the war. About 800,000 people are killed including over 400,000 Jews die, including Jews sent in by Slovakia. NOTE: So this doesn't get taken as Holocaust Denial I'd like to stress that this is a fictional alternative history. In OTL over 12 million people die including over 6 million Jews. This is almost the entire population of Jews that had lived in Germany and Czechoslovakia before the war. Most of the surviving Jews were liberated from their ghettos in Slovakia by the Soviets before being shipped to Germany. Only a few are able to conceal their identity throughout the existence of the Third Reich.
Colonization of Antarctica
The Germans claimed New Swabia, a territory in Antarctica as their own. Expeditions between 1939 and 1941 confirmed it was a valueable whaling spot. The town of Hitlerburg was founded in New Swabia in 1943 with only a couple thousand people. A military base is present there. From the start its economy is not self-sufficient relying almost entirely on German aid. Work progresses towards discovering valueable mining spots. In a few years after a few mining spots have opened and after whaling and fishing has picked up the economy is better, but still dependent on German aid.
In 1944 Norway reacts to Germany's colonization of Antarctica, claiming that is occupying Norwegian territory. In 1948 shortly after the death of Adolf Hitler a fleet of Norwegian ships lands at Hitlerburg, destroying the base in a surprise attack and taking the town. It is renamed Haakonheim. Germany declares war. This peaks world interest in Antarctica. The United States and Soviet Union declare portions of the unclaimed Marie Byrd Land to be theirs after launching explorations. A few of these overlap. In 1949 Germany successfully invades Norway's coast. Norway, fearing a potential defeat appeals to the United States. The United States agrees to assist Norway in exchange for a portion of its Antarctic territory. Norway accepts. In 1950 Germany is expelled from Norway with the help of American forces. An uprising in Bohemia and Moravia takes place. Germany is invaded by American and Norweigian forces and is overrun in 1951. The Treaty of Berlin grants independence to the Czech Republic as well as some territory. In additional a small piece of southeastern Germany is turned into the Republic of Sorbia. A democratic government is put in place.