"The Moscow Kremlin is a historic fortified complex at the heart of Moscow, overlooking the Moskva River (to the south), Saint's Basil's Cathedral and Red Square (to the east) and the Alexander Garden (to the west). It is the best known of kremlins (russian citadels) and includes four palaces, four cathedrals and the enclosing Kremlin Wall with Kremlin Towers. The complex serves as the official residence of the President of Russia.
The existing Kremlin walls and towers were built by Italian masters over the years 1485 to 1495. The irregular triangle of the Kremlin wall encloses an area of 275,000 square meters (68 acres). Its overall length is 2235 meters (2444 yards), but the height ranges from 5 to 19 metres, depending on the terrain. The wall's thickness is between 3.5 and 6.5 meters. Originally there were eighteen Kremlin towers, but their number increased to twenty in the 17th century. All but three of the towers are square in plan. The highest tower is the Spasskaya.The Spasskaya Tower is the main tower with a through-passage on the eastern wall of the Moscow Kremlin, which overlooks the Red Square. It was built in 1491. The Spasskaya Tower was the first one to be crowned with the hipped roof in 1624–1625 by architects Bazhen Ogurtsov and Christopher Galloway. According to a number of historical accounts, the clock on the Spasskaya Tower appeared between 1491 and 1585. It is usually referred to as the Kremlin clock.
In 1935, the Soviets installed a red star instead of a two-headed eagle on top of the Spasskaya Tower. The height of the tower with the star is 71 m. In August 2010 above the gate the icon of Savior Smolensky was restored.