Coming south from Flensburg, Rendsburg was a very different kind of stop. The old centre is there, but the reason the city interested us was much more obvious from a distance: the enormous steel railway bridge over the Kiel Canal and the ships passing underneath it.
Rendsburg has been shaped by borders and water for almost its entire history. The settlement developed on islands in the River Eider, which for centuries marked an important frontier between the Danish and German worlds. A castle existed here by around 1100, and in the early thirteenth century it was recorded as Reinholdsburg, the name from which Rendsburg eventually developed. The town itself is first mentioned as a city in 1253.
Its position made it strategically important. Rendsburg changed between Danish and German spheres of influence several times, and by the end of the seventeenth century it had become an enormous fortress. After major expansion between 1669 and 1695, it was considered the largest fortress in the Danish monarchy after Copenhagen.
The relationship with Denmark continued for centuries. In 1848, during the Schleswig-Holstein uprising against Danish rule, rebels took control of the fortress and Rendsburg briefly became the seat of the provisional Schleswig-Holstein government. Danish authority returned after the revolt failed, but the situation changed permanently after the war of 1864. By 1867 Rendsburg had become part of the Prussian province of Schleswig-Holstein.
Water was just as important as politics. The first major artificial waterway through this area was the Schleswig-Holstein Canal, later called the Eider Canal, which opened in 1784. It connected Kiel with the Eider and provided a route between the Baltic and North Seas, although ships still had to follow the winding river for much of the journey.
A much more ambitious solution followed in the nineteenth century. Between 1887 and 1895, Germany constructed the Kaiser Wilhelm Canal, now the Nord-Ostsee-Kanal or Kiel Canal. It created a direct shipping route between the North Sea at Brunsbüttel and the Baltic at Kiel-Holtenau, avoiding the long journey around Denmark.
Rendsburg suddenly found itself divided by one of Europe’s most important artificial waterways.
Today the canal is the part of the city that is hardest to ignore. Large container ships, tankers, cargo vessels and cruise ships pass through what otherwise looks like a surprisingly narrow strip of water. Watching a substantial ocean-going ship move slowly past grass, cycle paths and houses is one of the stranger sights in northern Germany.
Then there is the bridge.
The Rendsburg High Bridge was built between 1911 and 1913 to carry the railway between Neumünster and Flensburg across the canal. The steel structure is almost 2.5 kilometres long, while the railway approaches make the complete engineering work considerably longer. Ships have roughly 42 metres of clearance beneath it.
The height created another problem. Rendsburg railway station is close to the canal and much lower than the bridge, so trains could not simply climb directly towards it. Engineers solved this by building the Rendsburg Loop, a huge railway curve that allows trains to gain or lose height gradually before reaching the bridge.
The most unusual part, though, hangs underneath.
The Schwebefähre, or transporter ferry, crosses the canal suspended from the High Bridge. Rather than being a normal boat, its platform hangs from cables attached to a carriage running beneath the bridge structure. It carries pedestrians, cyclists and vehicles between Rendsburg and Osterrönfeld.
That immediately mattered to us because we were travelling with the motorhome. We specifically checked whether it could use the transporter ferry: vehicles are permitted up to 3.5 tonnes, exactly the weight category of our motorhome, but it was stil not allowed. The ferry normally crosses at fifteen-minute intervals and is free.
We did not need to invent an excuse to be interested in it. A ferry hanging from a railway bridge and carrying vehicles across a working ship canal is strange enough on its own.
The present gondola is actually new. In January 2016, the previous transporter ferry collided with the cargo ship Evert Prahm and was so badly damaged that it could not return to service. Rendsburg then spent six years without one of its best-known landmarks. A replacement, deliberately designed to resemble the original while using modern equipment, finally entered service in March 2022.
There are other ways across the canal. Road traffic can use the tunnel opened in 1961, while pedestrians and cyclists have their own tunnel from 1965. Farther east, the A7 crosses on the Rader High Bridge, another enormous structure that is currently being replaced.
The canal bank itself is probably the simplest place to understand Rendsburg. There is a long promenade where ships pass almost directly in front of you, and the city even has an extraordinarily long continuous bench beside the water. The point is not really the bench itself; it is that the canal has turned ship watching into a normal local activity.
Rendsburg’s old centre still has traces of its much earlier history, including the Altstädter Markt, St Mary’s Church and the old town hall, but the city’s strongest identity today comes from nineteenth- and twentieth-century engineering.
That was what made Rendsburg work for this part of our journey. After Flensburg and the Danish border region, we arrived at another place whose history is tied to the relationship between Scandinavia and continental Europe, but here the connection is physical.
Trains cross above the canal, ships pass underneath them, cars disappear into a tunnel below the water and a small platform hangs from the railway bridge carrying local traffic from one bank to the other.
Rendsburg is not difficult to understand once you reach the canal. The whole city seems to have been built around the problem of getting people, trains and ships past each other.