Visit a centuries old fortresses museums cathedrals and discover the citys heart on this 5 hour private tour of the kremlin and the red square a unesco world heritage site and the oldest and largest fortress in russia on the kremlin portion you will see the tsar cannon tsar bell 4 cathedrals assumption cathedral annunciation cathedral archangel cathedral cathedral of the twelve apostles4 palaces from outside great kremlin palace state kremlin palace terem palace poteshny palac