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 metropolis is a
popular tourist destination. Significant industries also include IT,
pharmaceuticals, biomedical engineering, clean tech, biotechnology,
construction and electronics.