Troldborg Ring

The Troldborg Ring is an Iron Age fortification in Vejle Municipality in Denmark, west of the city of Vejle. It is located at a natural spring on a high point overlooking the Vejle River Valley. The surrounding area is a steep ravine known as the Devil's Valley (). The site consists of a raised area of about surrounded by a circular rampart (). One side is protected by a steep drop of to the valley floor, while the other side features a , moat.
The Troldborg Ring was built around the years 100-200 during a period of turbulence in Denmark, and it was used until around the year 400. It likely served as a refuge during times of violence rather than a permanent dwelling. It is located north of the former Ravning Bridge over Vejle River, built in 979-980 during the Viking Age. Its placement suggests that the area was strategically important even before the bridge was built. A considerable amount of ash from massive fires has been found at the site, although the source and timing of these fires is unclear.