 The Route of Emperors and Kings is an international touristic route leading from Regensburg to Budapest, calling in Passau, Linz and Vienna.The international consortium "ARGE Die Donau-Straße der Kaiser und Könige", comprising ten tourism organisations, shipping companies, and cities, strives for the conservation and touristic development of the Danube region.In medieval Regensburg, with its maintained old town, stone bridge and cathedral, the Route of Emperors and Kings begins.