Brno, located at the confluence of the Svitava and Svratka rivers, is the principal city in the Moravia region of the Czech Republic, and is the country's second-largest city. It is a well known college town, being home to thirteen different institutions of higher learning, such as the Brno University of Technology, Masaryk University, and Mendel University. Sights of interest in Brno include Špilberk Castle, the 13th-century castle-turned-prison; the Cathedral of St. Peter and Paul, dating from the 15th century and perhaps the most noteworthy building in the city skyline; and the Villa Tugendhat, a Modernist architectural marvel designed by Reich and Mies van der Rohe, which is a UNESCO World Heritage Site.