Tsar Cannon

Tsar cannon in Moscow's Kremlin.
Photo by N.I.Zharkikh, September 6, 1976.

Near this cannon is always crowded. Indeed, a look at that. Cannon cast in 1586, its calibre – 890 mm. Its exact purpose is unknown. It is impossible to fire kernels by it – its walls are too thin. It has been suggested that it had to do a psychological effect on messengers (especially Crimean), demonstrating threatening military force.