Its , inhabitants as of make it the fifth-most populous city in Germany. The city is the heart of the larger Rhine-Main metropolitan region, which has a population of more than 5. Frankfurt is one of the de facto four main capitals of the European Union alongside Brussels , Luxembourg and Strasbourg , as it is home to the European Central Bank , one of the institutional seats of the European Union, while Frankfurt's central business district lies about 90 km 56 mi northwest of the geographic center of the EU at Gadheim in Lower Franconia.
Like France and Franconia , the city is named after the Franks. Frankfurt is the largest city in the Rhenish Franconian dialect area. 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 , as a site of Imperial coronations ; it lost its sovereignty upon the collapse of the empire in , regained it in and then lost it again in , when it was annexed though neutral by the Kingdom of Prussia.
It has been part of the state of Hesse since Frankfurt is culturally, ethnically and religiously diverse, with half of its population, and a majority of its young people, having a migrant background. A quarter of the population consists of foreign nationals, including many expatriates.
In , Frankfurt was home to 1, ultra high-net-worth individuals , the sixth-highest number of any city. As of , Frankfurt is the 13th-wealthiest city in the world and the second-wealthiest city in Europe after London. Frankfurt is a global hub for commerce, culture, education, tourism and transportation, and is the site of many global and European corporate headquarters. Due to its central location in the former West Germany , Frankfurt Airport became the busiest in Germany , one of the busiest in the world, the airport with the most direct routes in the world, and the primary hub for Lufthansa , the national airline of Germany and Europe's largest airline.
Automotive, technology and research, services, consulting, media and creative industries complement the economic base. Messe Frankfurt is one of the world's largest trade fairs. The city also has 93 consulates, among which the largest is the US Consulate General. The city is one of two seats of the German National Library alongside Leipzig , the largest library in the German-speaking countries and one of the largest in the world.
