Varbola was the largest ring fort and trade center in Estonia, in the Harju province in the 10th-12th century. Chronicler Henry of Latvia mentions Castrum Warbole besieged in 1211 for a few days by Mstislav Mstislavich the Daring from Novgorod. During the crusade of the Order of Livonian Brothers of the Sword, we know about the next siege of Varbola. The defenders then asked for peace conditions. Volkwin Schenk, the master of the Livonian Order, ordered the accepting of Christianity and giving the hostages. The offer was accepted by the defenders of the fort. Hosts were released only at the request of the emissary of the Danish king Valdemar II, who in 1238 took control of northern Estonia. From then Varbola became the property of the king of Denmark. The stronghold lost its importance only in the second quarter of the fourteenth century, after it played an important role in the anti-Christian and anti-German uprising on the Night of Saint George from 1343. In the 16th and 17th centuries the fortress area served as a cemetery.
Earth – stone fortifications had a form similar to a circle. The length of the ramparts was about 580 meters and 8 to 10 meters high from the outside. Two entrances, one from the west and one from the east, were protected by gate towers. In the middle of the fortress there was a 13-meter deep well, and in the courtyard there were about 90 objects, mostly on rectangular plan, some with stoves for residential purposes, some with floors and foundations built of limestone slabs.
Until now, parts of the Varbola with rampart length of 580 meters and a height of a few meters with the remains of limestone walls have survived. Entrance to the fort is free.