These hop-on, hop-off buses cover six routes with over 50 stops around Vienna. Popular routes include one that follows the Ringstrasse and makes a detour to Stephansplatz; Hundertwasserhaus and sights east of the Danube Canal, such as the Prater and UNO City; and Schönbrunn and Belvedere. All buses depart from directly outside the Staatsoper. The website has route maps.