Heilbronn (haɪlˈbʁɔn) is a city in northern Baden-Württemberg, Germany, surrounded by Heilbronn District. With over 126,000 residents, it is the sixth-largest city in the state. From the late Middle Ages on, it developed into an important trading centre. At the beginning of the 19th century, Heilbronn became one of the centres of early industrialisation in Württemberg. Heilbronn's old town was completely destroyed during the air raid of 4 December 1944 and rebuilt in the 1950s. Today Heilbronn is the economic centre of the Heilbronn-Franken region. Heilbronn is known for its wine industry and is nicknamed Käthchenstadt, after Heinrich von Kleist's Das Käthchen von Heilbronn. Heilbronn is located in the northern corner of the Neckar basin at the bottom of the Wartberg (308 m). It occupies both banks of the Neckar, and the highest spot inside city limits is the Schweinsberg with a height of 372 meters. Heilbronn is adjacent to the Swabian-Franconian Forest Nature Park and is surrounded by vineyards. Heilbronn and its surroundings are located in the northern part of the larger Stuttgart metropolitan area. The city is the economic center of the Heilbronn-Franken region and is one of fourteen such cities in the Baden-Württemberg master plan of 2002. It also serves Abstatt, Bad Rappenau, Bad Wimpfen, Beilstein, Brackenheim, Cleebronn, Eberstatt, Ellhofen, Eppingen, Flein, Gemmingen, Güglingen, Ilsfeld, Ittlingen, Kirchardt, Lauffen am Neckar, Lehrensteinsfeld, Leingarten, Löwenstein, Massenbachhausen, Neckarwestheim, Nordheim, Obersulm, Pfaffenhofen, Schwaigern, Siegelsbach, Talheim, Untergruppenbach, Weinsberg, Wüstenrot, and Zaberfeld as a regional economic centre. Heilbronn shares a border with the following cities and towns, all part of Heilbronn County and listed here clockwise from the North: Bad Wimpfen, Neckarsulm, Erlenbach, Weinsberg, Lehrensteinsfeld, Untergruppenbach, Flein, Talheim, Lauffen am Neckar, Nordheim, Leingarten, Schwaigern, Massenbachhausen and Bad Rappenau.