Chemnitz (1953–1990: Karl-Marx-Stadt, Czech: Saská Kamenice) is a city in Eastern Germany. With a population of approximately 245,000 in its city limits, Chemnitz is the third largest city of the Free State of Saxony. Located in western Saxony in the northern foothills of the Ore Mountains, it is a part of the Saxon triangle metropolitan area comprising 3.5 million people. First documented in 1143, Chemnitz evolved into one of the most important industrial cities of Germany in 19th and the beginning 20th century. In 1953, the city was renamed Karl-Marx-Stadt after the philosopher, political economist, and revolutionary Karl Marx. After the reunification of Germany in 1990, the city regained its original name and has the status as independent city, which is not part of any county and seat of the government region Regierungsbezirk Chemnitz. Chemnitz is one of the most important East German cities in economy, culture and science. The city's economy is based on the service sector and manufacturing industry. The Chemnitz University of Technology with about 10,000 students is the centre of scientific life.