The monumental Thun Castle was built in the mid-13th century, but the current appearance dates mainly from the 16th and 17th centuries. The Spanish style gate built in 1566 in Moorish style, probably after Giorgio Thun was visited in Spain. The most famous room is the seventeenth-century Bishop's Room, entirely covered of pine wood, with a coffered ceiling and a tiled stove.
Today Thun castle is open to the public.
Narikala is an ancient fortress overlooking Tbilisi, the capital of Georgia, and the Kura River. The fortress consists of two walled sections on a steep hill between the sulphur baths and the botanical gardens of Tbilisi. On the lower court there is the recently restored St Nicholas church. Newly built in 1996–1997, it replaces the original 13th-century church that was destroyed in a fire. The new church is of 'prescribed cross' type, having doors on three sides. The internal part of the church is decorated with the frescos showing scenes both from the Bible and history of Georgia.
The fortress was established in the 4th century and it was a Persian citadel. It was considerably expanded by the Umayyads in the 7th century and later, by king David the Builder (1089–1125). Most of extant fortifications date from the 16th and 17th centuries. In 1827, parts of the fortress were damaged by an earthquake and demolished.