St. Stephen's Cathedral is the mother church of the Roman Catholic Archdiocese of Vienna and the seat of the Archbishop of Vienna, Christoph Cardinal Schönborn. Founded in 1137 following the Treaty of Mautern, the partially constructed Romanesque church was solemnly dedicated in 1147 to Saint Stephen in the presence of Conrad III of Germany, Bishop Otto of Freising, and other German nobles who were about to embark on the Second Crusade.

Schönbrunn Palace was the main summer residence of the Habsburg rulers. The 1,441-room Rococo palace is one of the most important architectural, cultural, and historic monuments in the country. Since the mid-1950s it has been a major tourist attraction.

To most visitors, the island is known as a recreational area with bars, restaurants and nightclubs. It has sports opportunities from rollerblading, cycling and swimming to canoeing. The Donauinselfest is an internationally well-known annual open air festival, and Europe's biggest event of this kind, with over 3 million visitors. It takes place at the end of June