Kärkna Abbey, now ruined, was a former Cistercian monastery in Estonia. The monastery was founded before 1233 by the Bishop of Dorpat, Hermann von Buxhoeveden, and settled by monks from Pforta Abbey, of the filiation of Morimond. An early destruction by heathen inhabitants of the district is mentioned in 1234. After attacks by Russian forces from the principality of Vladimir-Suzdal and the Novgorod Republic it was rebuilt in about 1240 as a fortress surrounded by a moat and a rectangular granite wall. In 1305 it was placed under Stolpe Abbey on the Peene in Pomerania, which had joined the Cistercian order the previous year. In August 1558 the monastery was destroyed at the beginning of the Livonian War. There are remains of the foundations and of the perimeter walls.
The rectangular church was about 47 metres long, and consisted of a single nave of five vaulted bays. Unusually for a Cistercian church it also had a crypt of 10 bays containing two aisles, which was used not only as a place of burial but also as a place of shelter during hostilities. To the south of the church were attached the conventual buildings in the usual form of three ranges arranged in a square round a cloister and a central courtyard, with the chapter house in the east range.References:
Roman Walls of Lugo are an exceptional architectural, archaeological and constructive legacy of Roman engineering, dating from the 3rd and 4th centuries AD. The Walls are built of internal and external stone facings of slate with some granite, with a core filling of a conglomerate of slate slabs and worked stone pieces from Roman buildings, interlocked with lime mortar.
Their total length of 2117 m in the shape of an oblong rectangle occupies an area of 1.68 ha. Their height varies between 8 and 10 m, with a width of 4.2 m, reaching 7 m in some specific points. The walls still contain 85 external towers, 10 gates (five of which are original and five that were opened in modern times), four staircases and two ramps providing access to the walkway along the top of the walls, one of which is internal and the other external. Each tower contained access stairs leading from the intervallum to the wall walk of town wall, of which a total of 21 have been discovered to date.
The defences of Lugo are the most complete and best preserved example of Roman military architecture in the Western Roman Empire.
Despite the renovation work carried out, the walls conserve their original layout and the construction features associated with their defensive purpose, with walls, battlements, towers, fortifications, both modern and original gates and stairways, and a moat.
Since they were built, the walls have defined the layout and growth of the city, which was declared a Historical-Artistic Ensemble in 1973, forming a part of it and becoming an emblematic structure that can be freely accessed to walk along. The local inhabitants and visitors alike have used them as an area for enjoyment and as a part of urban life for centuries.
The fortifications were added to UNESCO"s World Heritage List in late 2000 and are a popular tourist attraction.