A piece of armor plate (a gun shield) from the Russian cruiser Bayan
This gun shield from the Russian Cruiser < href = "http://en.wikipedia.org/wiki/Bayan_class_cruiser">Bayan is made of 3" thick steel. It was likely pierced by Japanese land artillery when Port Arthur was overrun in 1905. The Bayab was refloated after the war and used by the Japanese navy until 1920, then sunk as a target in 1930