Frankfurt, officially Frankfurt am Main (German: [ˈfʁaŋkfʊʁt ʔam ˈmaɪn] (listen); Hessian: Frangford am Maa, lit. "Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 763,380 inhabitants as of 31 December 2019 make it the fifth-most populous city in Germany. On the river Main (a tributary of the Rhine), it forms a continuous conurbation with the neighbouring city of Offenbach am Main and its urban area has a population of over 2.3 million. The city is the heart of the larger Rhine-Main metropolitan region, which has a population of more than 5.6 million and is Germany's second-largest metropolitan region after the Rhine-Ruhr region. Frankfurt's central business district, the Bankenviertel, lies about 90 km (56 mi) northwest of the geographic center of the EU at Gadheim, Lower Franconia. Like France and Franconia, the city is named after the Franks.