Berlin is the capital of Germany with a population of 3.5 million people. It was originally the capital of Prussia and became the capital of Germany in the 1800s. After World War 2, Berlin was divided by the Berlin Wall, with the eastern part under communist control and restricting travel to the western part, where the wall separated the two sides until it was torn down in the late 1980s. The document provides brief descriptions of popular tourist sites in Berlin like the zoo, Olympic stadium, forests, and gardens.