Red Square: St Basil's Catheral, Lenin's Tomb, and the Kremlin (click to enlarge)
Above you can see three of the Red Square's most important residents. In the distance and on the left of the photo is the aforementioned St Basil's Cathedral. Running from the center and off the right side is the Kremlin. Lenin's tomb is the shorter building that lies in front of the Kremlin wall. You can also see Spasskaya Tower left of the photograph center.
Spasskaya Tower (click to enlarge)
The Main gate into Red Square from the Kremlin is through Spasskaya Tower or the Kremlin Clock Tower. The clock weighs 25 tonnes and the hands measure 3 meters in length. The clock chimes ever 15 minutes, and if you are not within earshot of Red Square you can tune in to various radio stations across the country to hear them.