Heidelberg. Heidelberg is a university town in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. In the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. Located about 78 km south of Frankfurt, Heidelberg is the fifth-largest city in Baden-Württemberg. Heidelberg is part of the densely populated Rhine-Neckar Metropolitan Region. 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. Heidelberg is in the Rhine Rift Valley, on the left bank of the lower part of the Neckar in a steep valley in the Odenwald. It is bordered by the Königsstuhl and the Gaisberg mountains. The Neckar here flows in an east-west direction. On the right bank of the river, the Heiligenberg mountain rises to a height of 445 meters. The Neckar flows into the Rhine approximately 22 kilometres north-west in Mannheim. Villages incorporated during the 20th century stretch from the Neckar Valley along the Bergstraße, a road running along the Odenwald hills. Heidelberg is on European walking route E1. Since Heidelberg is among the warmest regions of Germany, plants atypical of the central-European climate flourish there, including almond and fig trees; there is also an olive tree in Gaisbergstrasse. Alongside the Philosophenweg on the opposite side of the Old Town, winegrowing was restarted in 2000. There is a wild population of African rose-ringed parakeets, and a wild population of Siberian swan geese, which can be seen mainly on the islands in the Neckar near the district of Bergheim. Heidelberg is a unitary authority within the Regierungsbezirk Karlsruhe. The Rhein-Neckar-Kreis rural district surrounds it and has its seat in the town, although the town is not a part of the district. Heidelberg is a part of the Rhine-Neckar Metropolitan Region, often referred to as the Rhein-Neckar Triangle. This region consists of the southern part of the State of Hessen, the southern part of the State of Rhineland-Palatinate, the administrative districts of Mannheim and Heidelberg, and the southern municipalities of the Rhein-Neckar-Kreis. The Rhein-Neckar Triangle became a European metropolitan area in 2005. Heidelberg consists of 15 districts distributed in six sectors of the town. In the central area are Altstadt, Bergheim and Weststadt; in the north, Neuenheim and Handschuhsheim; in the east, Ziegelhausen and Schlierbach; in the south, Südstadt, Rohrbach, Emmertsgrund, and Boxberg; in the southwest, Kirchheim; in the west, Pfaffengrund, Wieblingen, and a new district, named Bahnstadt, is built on land in Weststadt and Wieblingen. The new district will have approximately 5,000-6,000 residents and employment for 7,000. Further new residential space for 10,000-15,000 residents was made available in Patrick Henry Village following the departure of the US Armed Forces. The following towns and communes border the city of Heidelberg, beginning in the west and in a clockwise direction: Edingen-Neckarhausen, Dossenheim, Schriesheim, Wilhelmsfeld, Schönau, Neckargemünd, Bammental, Gaiberg, Leimen, Sandhausen, Oftersheim, Plankstadt, Eppelheim and Mannheim. Heidelberg has an oceanic climate, defined by the protected valley between the Pfälzerwald and the Odenwald. Year-round, the mild temperatures are determined by maritime air masses coming from the west. In contrast to the nearby Upper Rhine Plain, Heidelberg's position in the valley leads to more frequent easterly winds than average. The hillsides of the Odenwald favour clouding and precipitation. The warmest month is July, the coldest is January. Temperatures often rise beyond 30 c in midsummer. According to the German Meteorological Service, Heidelberg was the warmest place in Germany in 2009.