The site of the white stone tower of the 16th century, built by Pskov masters, was previously occupied by the Khan Tower called Nur-Ali, which played a crucial role in the defense of the Kazan Khanate - it contained the source of water. Ivan the Terrible found out about its location and blew the Tower up by digging a secret underground passage. This military trick allowed the defenders of the fortress to keep the siege for a long time.
When the Russian troops entered the Kazan fortress through the broken wall of the fortress, Ivan the Terrible came into the captured city through the ruins of Nur-Ali.
This is an example of how well intuition works in combination with clear strategy: storming of Kazan in 1552 after a series of failed attempts was successful because it was carefully planned, and the Russian army used all the latest military-engineering achievements of the era, which were not available for the enemy.
Unfortunately, because of the explosion, the source of water was lost. In the twentieth century, ground water under the Kazan Kremlin was thoroughly explored in an attempt to recover the spring, but the water was found not suitable for drinking. Back then, in the 16th century, the perseverance of the residents of Kazan, who were used to clean water, was undermined, and many of the defenders of the fortress fell not from arrows and spears, but from bad water.
The Tower of Muraleev (this is how the Russians referred to Nur-Ali) was a single-tiered tower with a jagged pinnacle and a wooden roof. The Tower acquired the second tier and a complex toggled passage already in the 17th century. It was also then that the white stone of the Tower was lined and reinforced with brick. The Tower, restored by Pskov masters, received the name of Nikolskaya Tower, but later it was renamed to Taynitskaya Tower - after the story about the secret unraveled by Ivan the Terrible.
Prior to the 1990s, the Taynitskaya Tower stayed true to its name, since it was the site where lovers would secretly meet.
After the restoration, which was carried out in the middle of the 20th century, people came up with multiple ways to use the updated second tier of the Tower with high-arched niches in the walls. Exhibitions and performances took place there, and a café was opened. The current plan is to host historic quests with riddles and puzzles in the Tower.