The Kazan Kremlin is the chief historic citadel of Tatarstan, situated in the city of Kazan. It was built on behest of Ivan the Terrible on the ruins of the former castle of Kazan khans. It was declared a World Heritage Site in 2000.
The Kazan Kremlin includes many old buildings, the oldest of which is the Annunciation Cathedral (1554-62), the only 16th-century Russian church to have six piers and five apses. Like many of Kazan's buildings of the period, it is constructed of local pale sandstone rather than of brick. The renowned Pskov architects Postnik Yakovlev and Ivan Shirjay (called Barma) were invited by the Tzar to rebuild Kazan Kremlin in stone. The cathedral bell tower was erected in five tiers at the urging of Ivan the Terrible and was scored to resemble the Ivan the Great Belltower in Moscow, but was pulled down by the Soviets in 1930.
The most conspicuous landmark of the Kazan Kremlin is the leaning Söyembikä Tower, which probably goes back to the reign of Peter the Great. A well-known legend connects the tower with the last queen of Kazan. Another recognizable architectural feature is the Spasskaya Tower, which anchors the southern end of the Kremlin and serves as the main entrance to the Kremlin. The Spasskaya Tower is named after the Spassky Monastery, which used to be located nearby. Among the monastery's buildings were the Church of St. Nicholas (1560s, four piers) and the Cathedral of the Saviour's Transfiguration (1590s, six piers). They were destroyed by the Communists during Joseph Stalin's rule.
The opening of the biggest mosque in Europe, the Qolşärif Mosque, was held in Kazan on June 24, 2005. Roughly 17,000 people gathered for the celebration. Delegations from forty countries attended the event. The facility was reconstructed on the site where presumably Kazan Khanate's principal mosque had been standing before 1552. Speaking at the ceremony, Tatarstan President Mintimer Shaeymiev said "the Qolşärif mosque is a new symbol of Kazan and Tatarstan... a bridge connecting... our past and future."