Salzburg is the fourth-largest city in Austria and the capital of the federal state of Salzburg. Salzburg's "Old Town" with its world famous baroque architecture is one of the best-preserved city centres in the German-speaking world, and was listed as a UNESCO World Heritage Site in 1997. The city is noted for its Alpine setting. It is the birthplace of Wolfgang Amadeus Mozart and the setting for parts of the musical and film The Sound of Music, which features famous landmarks in Austria, but focuses mainly on Salzburg. Salzburg is also a student city, with three universities. Salzburg is on the banks of the Salzach river, at the northern boundary of the Alps. The mountains to Salzburg's south contrast with the rolling plains to the north. The closest alpine peak – the 1972 m Untersberg – is only a few kilometers from the city center. The Altstadt, or "old town", is dominated by its baroque towers and churches and the massive Festung Hohensalzburg. This area is surrounded by two smaller mountains, the Mönchsberg and Kapuzinerberg as the green lung of the city. Salzburg is approximately 150 km east of Munich, Germany, and 300 km west of Vienna.Salzburg is a tourist favourite, with the number of tourists outnumbering locals by a large margin in peak times. In addition to Mozart's birthplace noted above, other notable places include: The fortress Hohensalzburg on a hill dominating the old town is one of the largest castles in Europe, with views over Salzburg. Skiing is a key attraction during winter. Salzburg itself has no skiing facilities, but it acts as a gateway to skiing areas to the south. During the winter months its airport receives a large number of charter flights from around Europe.