The white limestone walls of the Kazan Kremlin run for almost two kilometres around the citadel, with thirteen towers surviving from the 16th and 17th centuries. The Spasskaya Tower at the southern gate is the main visitor entrance — a tall white tower with a green spire and the clock above the arch, finished in the 1560s by Postnik Yakovlev's Pskovian masons.
Walking the line of the walls from outside, especially the south and east faces above the embankment, gives the best sense of how the citadel sits on its cliff above the Kazanka. There is no continuous wall walk for visitors, but several of the towers and short stretches of the walkway can be visited from inside the Kremlin grounds.