Frankfurt am Main is the largest city in the German state of Hesse and the fifth largest city of Germany. Situated on the Main River, it has a population of approximately 650,000 (but about 5 million in its metropolitan area). Among English speakers it is usually known as simply Frankfurt, but Germans call it by its full name so as to distinguish it from another Frankfurt in Germany, Frankfurt an der Oder. It was once called Frankfort-on-Main in English, a direct translation of Frankfurt am Main. The three pillars of Frankfurt's economy are finance, trade fairs, and transport; it is the transport hub of Germany. Frankfurt has been Germany's financial capital for centuries. Frankfurt is often called "Bankfurt" or "Mainhattan" (derived from the local Main River). It is one of only three European cities that have a significant number of high-rise skyscrapers. With 9 skyscrapers taller than 150 meters (492 feet) in 2004, Frankfurt is second behind Paris (La Défense and Montparnasse: 12 skyscrapers taller than 150 meters, not counting the Eiffel Tower), but ahead of London (Canary Wharf and City: 8 skyscrapers taller than 150 meters). The city of Frankfurt contains the tallest skyscraper in Europe, the Commerzbank Tower. In Germany, only Frankfurt and Düsseldorf have high-rise skyscrapers. Frankfurt is renowned for its finance industry, on a par with London and Paris, as well as for its central location in Western Europe, surrounded by the most populous areas of Europe. It has a first-class infrastructure and a major international airport: Frankfurt International Airport. It is the second or third busiest in Europe, depending on the data used. Passenger traffic at in 2003 was 48,351,664, second in Europe behind London Heathrow Airport (63,487,136), almost in a tie with Paris Charles de Gaulle Airport (48,220,436). Frankfurt has a huge number of institutions, among them its university, Johann Wolfgang Goethe-Universität, as well as a number of museums, most of them lined up along the Main river on the Museumsufer (museum shore) and a large botanical garden, the Palmengarten. The best-known museums are the Städelsches Kunstinstitut und Städtische Galerie, called Städel, and the Naturmuseum Senckenberg. The Museum für moderne Kunst (Museum of Modern Art) and Schirn Kunsthalle (Schirn Art Galery) are also notable.