Berlin is the capital city and a state of Germany. It is the country's largest city in area and population, and the second most populous city in the European Union.

Berlin is one of the most influential centers in European politics, culture and science. The city serves as an important junction of continental transportation and is home to some of the world's most prominent universities, research faculties, and museums. Berlin is a major tourist destination and is recognized for its diverse range of convention venues and media outlets.

The rapidly changing metropolis at present enjoys an international reputation for its festivals, vibrant nightlife, contemporary architecture, and avant-garde arts.Being home to people from over 180 nations, Berlin is a magnet for individuals who are attracted by its liberal lifestyle, urban eclecticism, and artistic freedom.

First documented in the 13th century, Berlin became the capital of the Kingdom of Prussia in 1701 and of the German Empire in 1871. It remained so during periods of Weimar Republic and Third Reich until 1945. After World War II, the GDR (East Germany) claimed East Berlin as its capital, while West Berlin was a West German enclave surrounded by East Germany. Following the reunification in 1990, Berlin again became the capital of Germany.

Berlin is located in eastern Germany, about 70 kilometers (40 miles) west of the border with Poland. Berlin's landscape was shaped by ice sheets during the last ice age. The city center lies along the river Spree in the Berlin-Warsaw Urstromtal (ancient river valley), formed by water flowing from melting ice sheets at the end of the last Ice Age. The Urstromtal lies between the low Barnim plateau to the north, and the Teltow plateau to the south. In Spandau, Berlin's westernmost borough, the Spree meets the river Havel, which flows from north to south through western Berlin. The course of the Havel is more like a chain of lakes, the largest being the Tegeler See and Großer Wannsee. A series of lakes also feeds into the upper Spree, which flows through the Großer Müggelsee in eastern Berlin.

Substantial parts of present-day Berlin extend onto the low plateaus on both sides of the Spree Valley. Large parts of the boroughs Reinickendorf and Pankow lie on the Barnim plateau, while most of the boroughs Charlottenburg-Wilmersdorf, Steglitz-Zehlendorf, Tempelhof-Schöneberg, and Neukölln lie on the Teltow plateau. The borough of Spandau lies partly within the Berlin Urstromtal and partly on the Nauen Plain, which stretches to the west of Berlin. The highest elevations in Berlin are the Teufelsberg in the borough of Charlottenburg-Wilmersdorf and the Müggelberge in the borough of Treptow-Köpenick. Both hills have an elevation of about 115 meters (377 feet). The Teufelsberg is in fact an artificial pile of rubble from the ruins of World War II.