Estonia - Kuressaare Fortress

"..The most valuable part of Kuressaare Fortress, in Saaremaa island, is its core a bishop's castle erected mainly in the 14th century in Late Gothic style (first mentioned in 1381). It is threestoried structure of the Konventshaus type built on a strictly quadrangular ground plan after models of European order architecture, with a powerful 7-story Defence Tower on the north corner and a more slender 6-story Watch Tower on the east corner. The building material, a local brand of limestone known as Saaremaa dolomite, is easy to work and has lent the building its characteristic decor. Surrounding the medieval castle is Kuressaare Fortress a 15th-17th century system of bastions, curtains, ravelins and moats..." Source: UNESCO World Heritage Tentative List

Kuressaare Castle, Saaremaa island, Estonia. Nice stamps used. Thanks to Heidi of Estonia.