For German speaking interested people I recommend the documentary series "Land zwischen den Strömen" with three episodes about Northern Germany. The camera team joined a classic flat-bottomed boat on its journey through rivers and canals presenting local highlights and historical sights.
The three episodes can be downloaded from this public source (hope it works without geofencing):
https://mediathekviewweb.de/#query=Land%20zwischen%20den%20Str%C3%B6men
Enjoy the journeys.