Sudetenland
The Sudetenland was a mountainous area of Czechoslovakia. The name comes from the Sudetes, a mountain range, but it was also used for other places in Bohemia in which mostly-German people lived. They wanted their homes to be part of Germany, not Czechoslovakia. Nazi Germany took small parts of the Sudetenland from Czechoslovakia in September 1938.  After the Munich Agreement, they took the rest of Sudetenland, which contributed to the start of World War II.