Spasskaya Tower
Also of interest are the towers and walls, erected in the 16th and 17th centuries but later reconstructed; the Qol-Şarif Mosque, which has been rebuilt inside the citadel; remains of the Saviour Monastery (a 16th-century cathedral demolished by the Bolsheviks) with the Spasskaya Tower; and the Governor's House (1843–53), designed by Konstantin Thon, now the Palace of the President of Tatarstan.