Dinner gong

This distorted fragment of steel is a piece of armour plating from the British battlecruiser HMS New Zealand, which was struck by a German shell during the Battle of Jutland in 1916. The fragment was later mounted for use as a dinner gong in the ship's wardroom.

A lucky ship
HMS New Zealand was luckier than three other British battlecruisers involved in the Battle, which blew up when hit because of inadequate armour plating and the 'flash' from the exploding shells igniting their stored ammunition.