Berlin is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constituent states, Berlin is surrounded by the State of Brandenburg and contiguous with Potsdam, Brandenburg's capital. Berlin's urban area, which has a population of around 4.5 million, is the second most populous urban area in Germany after the Ruhr. The Berlin-Brandenburg capital region has over six million inhabitants and is Germany's third-largest metropolitan region after the Rhine-Ruhr and Rhine-Main regions.
Berlin is a world city of culture, politics, media and science. Its economy is based on high-tech firms and the service sector, encompassing a diverse range of creative industries, research facilities, media corporations and convention venues.
The city is well known for its festivals, diverse architecture, nightlife, contemporary arts and a very high quality of living.