Danube
The Danube flows through many cities, including four national capitals (shown below in bold), more than any other river in the world. Ordered from the source to the mouth they are:
The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania and by river ships to Kelheim, Bavaria, Germany; smaller craft can navigate further upstream to Ulm, Württemberg, Germany. About 60 of its tributaries are also navigable.
Wachau
The Danube River has a good network consisting of an inland navigation system. The Wachau valley historic sights can be visited by steamer boats; the best season to visit is between May and September. Autobahn services are also available from Vienna to visit all the important places in the Wachau. The well-developed road network between Melk and Krems follows the contour of the valley. However, there are no bridges across the Danube River in this region, and ferries are the only way to cross the river.Melk is a small town on the bank of the Danube at the start of the Wachau region at an elevation of . An ancient town with its historicity linked to the Romans (as a border post) and also to Babenbergs' times (as their strong fortress), known then as the Namare Fort, which the residents call as the Medelke of the Nibenlunggenlied or the Babenberg fortress. Its present population is reported to be 5300. Its large enticing popularity is on account of the Benedictine abbey (founded in 1089 AD), perfect example of a "Baroque synthesis of the arts" which forms the western gateway to the Wachau, which is located on a high cliff. There is baroque gateway at the entrance.