"Kremlin" (actually kreml) is the Russian word for citadel, and that's exactly what the Moscow Kremlin was: a medieval walled city on a hill above the Moscow River. Long ago, of course, the city grew far beyond the walls, but the citadel remained the seat of government.
Visitors enter the Kremlin through the Trinity Tower
on the west side.
Beyond the tower on the right is the Soviet-era Palace of
Congresses.
Inside the Kremlin walls is a mix of buildings, ranging from somewhat drab
Soviet-era government offices to antique churches, such as the
Cathedral of the Twelve Apostles (second from left) and the
Cathedral of the Assumption.
Along with the buildings
are monuments (including a large Lenin statue) and the Tsar
Cannon, the largest cannon ever built, and the Tsar
Bell, the world's largest bell.
Despite the abundance of buildings, the southeast part of the Kremlin
interior is a large garden, almost a small forest, with carefully
maintained walkways.
The most famous of the Kremlin's towers is the Spasskaya
(Savior) clock tower, also visible from Red Square, but there are eighteen
others, including the Tainitskaya and the
Beklemishevskaya, both seen here from the
walkway along the south side of the Kremlin interior.