The word Kremlin (Kreml in Russian) designates the fortress of a city, the old quarter where the cathedral and the sovereign’s palace were protected behind its walls. Those of the Kremlin in Moscow were originally made of wood in the 12C, then of white stone, and finally of red brick in the 15C, when the architectural complex took on its present form. Allow a day to explore the abundance of civil and religious buildings in this heart of Holy Russia.