The Moscow Kremlin is a historic fortified complex at the heart of Moscow, overlooking the Moskva River (to the south), Saint 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 the Russian Federation. The site has been continuously inhabited since the 2nd century BC, and originates from a Vyatich fortified structure (or "grad") on Borovitsky Hill where the Neglinnaya River flowed into the Moskva River. The Slavs occupied the south-western portion of the hill as early as the 11th century, as evidenced by a metropolitan seal from the 1090s, which was unearthed by Soviet archaeologists in the area.