Start with the ground, because the ground is the whole reason this wall exists. Between the Baltic inlet of the Schlei and the North Sea marshes, the Jutland peninsula pinches to a corridor of firm, sandy land, and for more than a thousand years every army, trader and pilgrim travelling between Scandinavia and the rest of Europe had to squeeze through it.
Archaeologists have found that the wall was not built once but many times, with timber, turf, clay and eventually brick used in successive centuries. The oldest dated phases go back to the early 700s, and the big expansions came under King Godfred in the early 800s and Harald Bluetooth in the later 900s. Later still came the brick facing of the twelfth century, which gave the monument the look of a medieval castle wall stretched across the countryside. Walking along it today, you read the rise and fall of kingdoms in the profile of a grass-covered bank.
The lanes nearby are the kind you want when you are looking for quiet. They run through arable fields and low woods, with little traffic except local farmers, and the surface is good if narrow. Corners are gentle, visibility is usually decent, and the horizon is wide. Dannewerk and Schuby are villages, with limited services, so fuel and food are best found in Schleswig, a short ride away, where there is a pretty old town and a lakeside promenade.
Nature has reclaimed much of the wall, and the banks are now home to wild flowers, rabbits and, in spring, skylarks that rise from the grass in a continuous trill. In winter the wind sweeps across the open land and the air smells of frost and ploughed clay. A short walk from the roadside, with the dull thud of boots on turf, lets you feel the size of the thing. It is a place for stopping and looking rather than for racing, and it rewards patience.