A rare German map of the Danube

A very rare map of the Danube river as surveyed by German engineers at the time of the Austro-Turkish War of 1737-9, when the river was an important frontier as well as a vital trade route to the east. The river is shown in three sections: from its source in Donaueschingen in the Black Forest to Kahlenbergerdorf on the outskirts of Vienna (shown in the upper map inset); from Vienna to Nicopol in Bulgaria (the main map); and from Bucharest to the Black Sea (lower inset). Nine more insets illustrate features of the river, including hazards and fishing techniques.