The Danube stretches from its source in the Black Forest in southern Germany to Sulina, the easternmost point of Romania, where the land promptly gives way to sand and the lapping waves of the Black Sea.
Unique among the major European rivers for travelling west to east rather than north to south, its 1,777-mile (2,850km) course currently crosses ten countries.
Serving for centuries as a bridge between Europe and Asia, the Danube has acted as a backdrop to global events since classical times.
Yet the Danube we have now has lost some 80% of its original flood plain, and only 30% of the river is free-flowing.
Though once again navigable along its whole length, fears remain, however, about the risk to its ecological health from the detritus of the heavy industries promoted at its eastern end during Soviet times.
As the poet Heinrich Heine once admonished a young Karl Marx to remember, ‘the difference between water and a river is that the latter has a memory, a past, a history’.
If the Danube has that in spades, it is up to us to ensure it also has a healthy future, too.