Eisenach is a town in Thuringia, Germany with 42,000 inhabitants, located 50 kilometres (31 miles) west of Erfurt, 70 km (43 miles) southeast of Kassel and 150 km (93 miles) northeast of Frankfurt. It is the main urban centre of western Thuringia and bordering northeastern Hessian regions, situated near the former Inner German border. A major attraction is Wartburg castle, which has been a UNESCO world heritage site since 1999. Eisenach was an early capital of Thuringia in the 12th and 13th centuries. St. Elizabeth lived at the court of the Ludowingians here between 1211 and 1228. Later, Martin Luther came to Eisenach and translated the Bible into German. In 1685, Johann Sebastian Bach was born here. During the early-modern period, Eisenach was a residence of the Ernestine Wettins and was visited by numerous representatives of Weimar classicism like Johann Wolfgang Goethe. In 1869, the SDAP, one of the two precursors of the Social Democratic Party of Germany (SPD) was founded in Eisenach. Car production is an important industry in Eisenach. The Automobilwerk Eisenach was founded in 1896. In the German Democratic Republic, the Wartburg was produced here. Eisenach is situated on the Hörsel river, a tributary of the Werra between the Thuringian Forest in the south, the Hainich mountains in the north-east and the East Hesse Highlands in the north-west.