The city's great sight is the 11th-century Bagrati Cathedral (Kazbegi; admission free; 9am-8pm) , which you'll see high on the Ukimerioni Hill across the river from the city centre There has been a fortress here since at least the 1st century AD; now there are remains from the 5th and 6th centuries, and late medieval fortifications. Occupied by the Turks, in 1769 it was bombarded by Solomon I and the Russian General Todleben from Mtsvane Kvavila.
The cathedral was commissioned by the first king of a unified Georgia, Bagrat III. An Arabic inscription (no longer visible) on the north wall gives us the exact date of completion: "When the floor was finished it was chronicon 223" (1003). The date is the oldest remaining example of Arabic numerals in Georgia. Intending to symbolize his unification of Georgia, Bagrat invested much of his personal prestige in the building of the cathedral. According to a chronicle of the time, at the cathedral's consecration, Bagrat "assembled the neighbouring rulers, the patriarchs and archbishops, the abbots of all the monasteries, and all the notables from the lower and higher parts of his realm and from all other kingdoms." Even in its present ruined state, you cannot but feel the grandeur and nobility of the structure and the sense of power and wonder that must have attended that consecration ceremony.
Like the Church of Oshki (now in Turkey) with which it is frequently compared, the Cathedral of Bagrat is a triconch with protruding sidearms to form the cross. The cupola was supported by four detached octagonal columns and the drum raised high above. With the windows in the conches, a light-filled open space was created. The extended western arm was separated into three aisles and furnished with galleries for the king's family. A three-story tower was added to the left side of the west facade; this probably served as the king's quarters or as the residence of the local archbishop. Somewhat alter the completion of the cathedral, but still in the first half of the 11th century, a portico with open arches was added to the south-west side. A little later this concept was repeated in front of the entryways on the west and south sides. Only ruins of the south portico remain today. These later embellishments were marked by elaborate, deeply incised stone carving on the capital and base of the pillars, the pillared entrances, and selected door and window frames. Mythical animals, human laces, and sometimes human faces on animal bodies predominate here, usually intertwined with rich leaf motifs. The technique is reminiscent of Romanesque capitals. This type of carving and iconography is in contrast to the overall conception of the stonemasonry of the cathedral, which utilizes more of the subdued classicism usually associated with Kumurdo. In such a concept, harmony of intent is expressed by the symmetrical disposition of the blind arcading, and the slender gables and windows.
Russian ambassadors who visited the church in the middle of the 17th century reported that the interior was covered with mosaics. Remnants of the design of the floor-broad circles interspersed with inlays of black, white, and red-are still visible at the eastern end of the building. The cathedral was sacked and destroyed by the Turks in 1691, since when it has been roofless and disused.
The ruined palace-citadel immediately east of the cathedral dates from the 6th century and in the 17th century was still reported by French and Russian travellers to be massively impressive. In 1769 King Solomon I of Imereti and the Russian General Todtleben bombarded the castle (which was then occupied by the Turks) from Mtsvane Kvavila hill across the river, reducing it to a ruin. What remains is still of interest: you can see wine cellars at the west end of the palace, a church in the middle, and parts of the medieval walls.
Since 1951 Georgian restorers have been working on the site. UNESCO has placed it on its World Heritage List, and it is currently being restored, a process necessitating the extensive use of unphotogenic scaffolding. There are plans to rebuild it fully, but even in its roofless, part-ruined condition it has a stately beauty matched by few churches in Georgia.