When the Vikings built their trading town of Hedeby at the head of the Schlei, a long narrow inlet of the Baltic, they chose a spot with a short portage to the North Sea rivers, making it one of the great crossroads of Northern Europe. To protect the isthmus between the two seas, the Danes built a long earthwork called the Danevirke, begun in the eighth century and strengthened for centuries after, with a rampart, a ditch and in places a brick wall added in the twelfth century by King Valdemar. Hedeby and the Danevirke are together a UNESCO World Heritage Site. The East Wall, the Ostwall, is the eastern arm of the system, running through the countryside near Kosel above the Schlei.
On the ground, the Danevirke looks like a long, grassy bank in a field, with a ditch beside it and trees growing on the top. It is easier to understand at the Danevirke Museum, near Dannewerk, which explains how the barrier was built, rebuilt and fought over, from the Viking age until the war of 1864, when the Danes withdrew from it in the face of Prussian and Austrian forces. The frontier it protected moved back and forth over centuries between Danish and German control, and this region of Schleswig has an unusually mixed identity, with Danish minority schools and Low German dialects.
The countryside is gentle farmland, with knobbly fields, hedgerows called Knicks, lakes and the long waters of the Schlei, and roads run in easy curves between villages. The flat horizons and big skies are typical of Schleswig-Holstein. Rider-friendly surfaces and moderate traffic make it a relaxed place, though wind off the Baltic can be strong. Summer is the busiest time on the Baltic coast, and spring and autumn are quieter. Mist hangs over the meadows in the morning.
Kosel, three kilometres away, is a village of about thirteen hundred people, and Eckernförde, six kilometres off, is a lively Baltic port with fuel, shops, a smokehouse tradition and a harbour full of boats. The city of Schleswig, with its fishing village Holm and its castle, Gottorf, is a short ride to the north-west. Try a smoked herring roll or a Kieler Sprotte, a smoked sprat, and a plate of Holstein pork with red cabbage. The Hedeby museum, a short drive away, has reconstructed Viking houses beside the water and is worth a visit on a dry day.