Söyembikä (various spellings, usually Suyumbike in English; in Cyrillic Сөембикә) was a Tatar princess, and regent of Kazan 1549-1551 during the minority of her son. In 1551 Ivan the Terrible captured the area, and the legend goes that he pressured the widowed princess to marry him. She consented to marry only if he could build the highest tower in Kazan in seven days, which he promptly did; so she jumped to her death from the top of the tower. In truth she was carted off to Moscow, re-married (her third) and died some time around 1554, while the tower was probably built at a much later date. It's 58 m tall, in tiers; it famously used to lean, but was stabilised and straightened in the 20th-century. You can admire it from the outside but you can't enter or climb it.