Berlin

Berlin is the capital of Germany, as well as its largest city by both area and population. With 3.7 million inhabitants, it has the highest population within its city limits of any city in the European Union. The city is also one of the states of Germany, being the third-smallest state in the country by area. Berlin is surrounded by the state of Brandenburg, bordering Brandenburg's capital Potsdam to the southwest. The urban area of Berlin has a population of over 4.6 million, making it the most populous in Germany. The Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Germany's second-largest metropolitan region after the Rhine-Ruhr region, as well as the fifth-biggest metropolitan region by GDP in the European Union.

Berlin was built along the banks of the Spree river, which flows into the Havel in the western borough of Spandau. The city includes lakes in the western and southeastern boroughs, the largest of which is Müggelsee. About one-third of the city's area is composed of forests, parks and gardens, rivers, canals, and lakes. First documented in the 13th century and at the crossing of two important historic trade routes, Berlin was designated the capital of the Margraviate of Brandenburg (1417–1701), Kingdom of Prussia (1701–1918), German Empire (1871–1918), Weimar Republic (1919–1933), and Nazi Germany (1933–1945). Berlin served as a scientific, artistic, and philosophical hub during the Age of Enlightenment, Neoclassicism, and the German revolutions of 1848–1849. During the Gründerzeit, an industrialization-induced economic boom triggered a rapid population increase in Berlin. 1920s Berlin was the third-largest city in the world by population.