The Roman navy is not the first thing most people associate with Cologne, but for almost two centuries the Rhine fleet, the Classis Germanica, had its main base here at Alteburg, just south of the Roman city. The fort sat on a terrace above the river in what is now the leafy district of Marienburg, near Bayenthal, and from here warships patrolled the Rhine, carried supplies and soldiers, and kept watch on the frontier. The site belongs to the Lower Germanic Limes, listed by UNESCO in 2021, though today it lies mostly under villas, streets and gardens, with only traces and information boards to show where it stood.
Marienburg is one of Cologne's grandest residential areas, with big houses set in green gardens along the river, and walking or riding slowly through its streets is a pleasant contrast to the dense city centre. Down at the river, the Rheinufer offers paths, views across to Poll and the bridges, and a sense of the big working waterway that the Romans controlled.
Riding in Cologne is typical German city riding: busy ring roads, tram tracks, many cyclists and frequent traffic lights. The old town has cobbled streets, and the low-emission rules and parking restrictions can make life complicated. Approach Alteburg along the Rhine from the south, and once your visit is over, head out to the Bergisches Land east of the river or the Eifel to the south-west for proper riding country.
You are in a city of a million people, so fuel, food and coffee are everywhere. In the centre, the cathedral is unmissable, and the Romano-Germanic Museum beside it holds the Dionysus mosaic and a wealth of finds from Roman Cologne, which was a major provincial capital called Colonia Claudia Ara Agrippinensium. Afterwards, sit in a traditional brewery tavern and drink Kölsch, the local beer, served in slim glasses by waiters who keep bringing new ones until you put a beer mat on top.
The Rhine at Alteburg is broad and brown, with barges sliding past and gulls crying over the water. It takes no great leap to swap the barges for oared galleys heading upstream on patrol, the city walls of Roman Cologne glinting on the rise behind them, and to realise that this stretch of river has been a busy workplace for two thousand years.