Flag of Heidelberg, Germany

Heidelberg (German: [ˈhaɪdl̩bɛʁk] ; Palatine German: Heidlberg) is the fifth-largest city in the German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of students, it is Germany's 51st-largest city. Located about 78 km (48 mi) south of Frankfurt, Heidelberg is part of the densely populated Rhine-Neckar Metropolitan Region which has its centre in Mannheim. Heidelberg is located on the Neckar River, at the point where it leaves its narrow valley between the Oden Forest and the Little Oden Forest, and enters the wide Upper Rhine Plain. The old town lies in the valley, the end of which is flanked by the Königstuhl in the south and the Heiligenberg in the north. The majority of the population lives in the districts west of the mountains in the Upper Rhine Plain, into which the city has expanded over time. Heidelberg University, founded in 1386, is Germany's oldest and one of Europe's most reputable universities. Heidelberg is a scientific hub in Germany and home to several internationally renowned research facilities adjacent to its university, including the European Molecular Biology Laboratory and four Max Planck Institutes. The city has also been a hub for the arts, especially literature, throughout the centuries, and it was designated a "City of Literature" by the UNESCO Creative Cities Network. Heidelberg was a seat of government of the former Electorate of the Palatinate and is a popular tourist destination due to its romantic cityscape, including Heidelberg Castle, the Philosophers' Walk, and the Baroque old town.