Kremlin

The Kremlin (Russian: Московский Кремль, Moskovskiĭ Kremlʹ) is a complex in Moscow and one of the city's three landmarks that Luigi has to visit in the game Mario is Missing! in order to rescue the city from Koopa Troopas. The Cannonball from the Emperor's Cannon, a cannon inside of the Kremlin and the largest one in the world, has been stolen during the events of the game. Upon returning it to the Kremlin, Luigi is rewarded 1,600 dollars.

Pamphlet Information from Mario is Missing!
''The Emperor's Cannon, in the Kremlin, is known in Russian as Tsar Pushka. It is the biggest cannon in the world, with a caliber of 89 centimers. Its barrel is 5.3 meters long. The cannon was cast in 1586 by Andrey Shchokhov [sic] and weighs a total of 40 tons. On the barrel is a likeness of Tsar Fyodor Ivanovich.''