Lilleborg is a ruined castle in the Almindingen forest. The castle was probably built in the middle of the 12th century as a royal fortress. It appears to have replaced the much larger fortress of Gamleborg which was only 700 metres away. The move could be explained by the fact that in 1149, three-fourths of Bornholm had been surrendered to Eskil, archbishop of Lund. As a result, King Sweyn III wanted to establish his own seat of power on the remaining fourth of the island. While it could not be compared to the archbishop's Hammershus, Lilleborg was nevertheless a fine stronghold and appears to have been easier to defend than the much larger Gamleborg. There is evidence suggesting the fortress burnt down in 1259 when Prince Jaromar of Rügen stormed and destroyed the 'king's stronghold' on Bornholm. However, coins minted after that date have been found, indicating it was inhabited after its storming.
Lilleborg's construction inland rather than on the coast has been compared to that of Refshaleborg on Borgø in Maribo lake. It had a large tower, 9.5 metres square, protecting the entrance to the courtyard. Its walls were 2.4 metres thick and from the top it was easy to hit anyone trying to attack. The fortress is further protected by a curtain wall which follows the cliff tops around the oval plateau. The interior was some 76 metres long and 41 metres wide. When its defenses were obsolete, the fort's stones were re-purposed for other buildings. From 2006 to 2011, restoration work was carried out at Lilleborg.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.