In 1945 a researcher discovered an old archaeological survey plan at the National Museum in Copenhagen. The circular earthwork on the plan looked exactly like the strange Viking Age fortress that had been excavated at Trelleborg then years earlier, but this stronghold was twice as large. When the ring fortress Aggersborg was discovered, one of the greatest mysteries in Danish history grew even bigger. Today we know of five ring fortresses, built under Harald Bluetooth in the late 10th century, all of which are UNESCO World Heritage sites. This book follows the archaeologists who uncovered the history of the largest of the fortresses – Aggersborg.
