Frankfurt was a city state, the Free City of Frankfurt, for nearly five centuries, and was one of the most important cities of the Holy Roman Empire; it lost its sovereignty in 1866.
Frankfurt has a 2015 population of 732,688 within its administrative boundaries, and is Germany's second-largest metropolitan region after Rhine-Ruhr.
A quarter of the population are foreign nationals, including many expatriates.
Frankfurt is an alpha world city and a global hub for commerce, culture, education, tourism and transportation.
It is the site of many global and European corporate headquarters. Frankfurt is the major financial centre of the European continent, with the HQs of the European Central Bank, German Federal Bank, Frankfurt Stock Exchange, Deutsche Bank, Commerzbank, DZ Bank, Kf W, several cloud and fintech startups and other institutes.
Automotive, technology and research, services, consulting, media and creative industries complement the economic base.
Its renowned cultural venues include the concert hall Alte Oper, Europe's largest English Theatre and many museums (e.g.
the Museumsufer ensemble with Städel and Liebieghaus, Senckenberg Natural Museum, Goethe House), the Schirn art venue at the old town.
Since the enlargement of the European Union in 2013, the geographic centre of the EU is about 40 km (25 mi) to the east of Frankfurt's CBD, the Bankenviertel.
Frankfurt is culturally and ethnically diverse, with around half of the population, and a majority of young people, having a migration background.
Frankfurt's skyline is shaped by some of Europe's tallest skyscrapers.
The city is also characterised by various green areas and parks, including the central Wallanlagen, the City Forest and two major botanical gardens, the Palmengarten and the University's Botanical Garden.
Major fairs include the Frankfurt Motor Show, the world's largest motor show, the Music Fair, and the Frankfurt Book Fair, the world's largest book fair.