Largest cannon ball

The world's largest cannon ball has a diameter of 91 cm (36 in) and weighs over 1 tonne (2,240 lb) when filled with its charge of 180 kg (400 lb) of gunpowder. It belongs to the Mallet mortar gun, which was designed by Robert Mallet (Ireland) and completed in March 1857. It is currently on display at the Royal Armouries, Fort Nelson, Hampshire, UK. Mallet's mortar required 35 kg (70 lb) of powder to fire such a projectile to reach its range of 2.4 km (1.5 miles) and to bury the charge to a depth of 9.1 m (30 ft) in soft earth, something that would cause the effect of a small earthquake and ultimately lead to the collapse of structures. The mortar is one of only two ever built, both of which were transferred to the Royal Armouries in 1925. They were made with the intention of being used to bombard the fortifications at Sebastopol from inland, during the Crimean War of 1854-56. Although they were not completed in time for their purpose, and have never been fired in aggression, one of the mortars was first test-fired on 19 October 1857.