Spasskaya Tower is at the southern end of the Kremlin and serves as its main entrance. The tower is named after the Spassky Monastery, which used to be located nearby. Among the monastery's buildings were the Church of St. Nicholas (1560s, four piers) and the Cathedral of the Saviour's Transfiguration (1590s, six piers). They were destroyed by the Communists during Stalin's rule.