The Söyembikä Tower, the leaning brick tower at the heart of the Kremlin, is perhaps the city's single most recognisable structure — a seven-tiered watchtower roughly 58 metres high with a marked tilt of nearly two metres off vertical. The base is medieval Tatar; the upper stages are 17th-century Russian. Like the Tower of Pisa, it leans because of soft foundations.
Visitors cannot climb the tower — there is no public access inside — but it stands open at all times in the centre of the Kremlin courtyard, framed by the Kul Sharif Mosque to the west and the Annunciation Cathedral to the east. The crescent at the top was added in the 1990s, restoring an earlier Tatar finial removed under Russian rule.