20^th World Bioenergy Congress and Expo

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 1806, regained it in 1815 and then lost it again in 1866, when it was annexed (though neutral) by the Kingdom of Prussia. It has been part of the state of Hesse since 1945. 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 2015, Frankfurt was home to 1909 ultra-high-net-worth individuals, the sixth-highest number of any city. Frankfurt is a global hub for commerce, culture, education, tourism and transportation, and rated as an "alpha world city" according to GaWC. It is the site of many global and European corporate headquarters. In addition, Frankfurt Airport is the busiest in Germany, one of the busiest in both Europe and the world, the airport with the most direct routes in the world, and the primary hub for Lufthansa, the national airline of Germany. Frankfurt is one of the major financial centers of the European continent, with the headquarters of the European Central Bank, Deutsche Bundesbank, Frankfurt Stock Exchange, Deutsche Bank, DZ Bank, KfW, Commerzbank, several cloud and fintech startups and other institutes. Automotive, technology and research, services, consulting, media and creative industries complement the economic base. Frankfurt's DE-CIX is the world's largest internet exchange point. Messe Frankfurt is one of the world's largest trade fairs. Major fairs include the Music Fair and the Frankfurt Book Fair, the world's largest book fair.