Varbola - Credit: Wikimedia Commons
The Varbola Stronghold (,Scriptores Rerum Livonicarum; Published 1853; p. 162 ) was the largest circular rampart fortress and trading centre built in Estonia, in Harju County () in the 10th – 12th centuries. Parts of the ruins of the long and high limestone wall of the fortress stand to this day. The long gateways with multiple gates were built to defend the entrances. In these sections higher defensive towers were erected. There was a deep well in the middle of the fortress and the territory held about 90 structures with furnaces for accommodation built with limestone floors and foundations.Varbola at guide to Estonia Read more on Wikipedia
Source: en.wikipedia.org