Valdemarsmuren, Medieval fortification in Schleswig-Holstein, Germany

Valdemarsmuren is a fortification wall that extends for several kilometers and was built from brick stone. The structure consists of a solid main wall with a frontal ditch and rests partly on older stone foundations.

The wall was built in the second half of the 12th century and represented an innovation in Scandinavian fortification design. It marked the shift from stone to brick as the main building material for large-scale defensive structures.

The wall takes its name from King Valdemar the Great, who had this section of the Danevirke main rampart reinforced in the second half of the 12th century. At Danish folk high schools it became customary to lay a stone from Valdemarsmuren as the foundation stone of new buildings.

A restored section about 75 meters long is accessible near the Danevirke Museum and offers a good view of the original construction. The location is easy to reach and allows visitors to examine the structure from both ground and elevated positions.

The wall's brick was the first use of fired brick in what is now Denmark, and the 80-metre stretch visible today shows the brick laid in mortar on a foundation of fieldstone. Since 2018 the wall has been part of the UNESCO World Heritage site of Hedeby and the Danevirke.