Ústí nad Labem (Czech pronunciation: [ˈuːsciː nad ˈlabɛm] ; German: Aussig) is a city in the northwest of the Czech Republic. It has about 90,000 inhabitants and is the capital of the Ústí nad Labem Region. The city is located at the confluence of the Elbe and Bílina rivers. Together with Chomutov, Teplice, Most and Děčín, Ústí nad Labem forms the Ústí nad Labem-Chomutov agglomeration with about 550,000 inhabitants. Ústí nad Labem was founded in the 12th century and became a royal town in 1249. However, its size and importance only grew significantly thanks to industrialisation in the 19th century. The city is a major industrial centre with a tradition in the chemical industry. It is both an active river port on the Elbe and an important railway junction. The city is a natural regional centre of education and home to the Jan Evangelista Purkyně University in Ústí nad Labem. Among the main landmarks of Ústí nad Labem are the Střekov Castle and the Church of the Assumption of the Virgin Mary with a leaning tower. A major tourist destination is the Ústí nad Labem Zoo.