The Viking ring fortress of Trelleborg, near Slagelse in Denmark.
Archaeologists in Denmark have found a ring-shaped Viking fortress on the island of Zealand, around 50km south of Copenhagen. It is the fifth circular fortress to be unearthed, and the first in more than 60 years.
Lasse Sonne, a Viking historian at the University of Copenhagen, said: "Although there were
Vikings in other countries, these circular fortresses are unique to Denmark. Many have given up hope that there were many of them left."
Like previously discovered ring fortresses, the Vallo Borgring is thought to date back to the late 10th century and the reign of Harald Bluetooth, the King who christianised Denmark and Norway.
Some historians contend the fortresses were constructed by his son Sweyn Forkbeard, the first Danish King of England, as a military training camp or barracks from which to launch his invasions of England.
Forkbeard seized London in 1013 and was declared King of England.
