The monuments of ancient culture and architecture are spread throughout the republic. The monuments represent different historical stages of the region: the appearance of the first people app. 100,000 years ago, forming of Finno-Ugric tribes and starting to appear of Turkic peoples app. in the 4th-8th centuries AD, establishing of the state of Volga-Kama Bulgaria by tribes of ancient Bulgars starting from the 8th century, islamisation by the end of the 10th century, incorporation of the Bulgar state into the Mongol Empire and later becoming a part of the Golden Horde, collapsing of the Horde in replacing by the Kazan Khanate in the 15th century, the siege of Kazan and falling of the Kazan Khanate to the Russian tsar Ivan the Terrible in 1552, and becoming of the region with capital Kazan as a part of the Russian Empire. All these historical periods are represented by monuments like the Bulgar fortification, the Bet’ki fortress, the Castle of Khan Bairash, the Citadel of Dzhuketau, and many others, and by the monuments of architecture like the Sviyazhsk museum-reserve of history and architecture and others.