Size
The Danevirke is about 30 km long overall, with a height varying between 3.6 and 6 m. During the Middle Ages, the structure was reinforced with palisades and masonry walls, and was used by Danish kings as a gathering point for Danish military excursions, including a series of crusader raids against the Slavs of the south Baltic. In particular, the 12th-century King Valdemar the Great reinforced parts of the Danevirke with a brick wall, which enabled a continued military use of the strategically important structure. The reinforced parts of the structure are consequently known in Danish as Valdemarsmuren (Valdemar's wall).
Read more about this topic: Danevirke