Siege cannon

Siege artillery (also siege guns or siege cannons) is the heavy guns designed to bombard fortifications, cities, and other fixed targets, as distinct from, e.g., field artillery. It is a class of siege weapon. They were capable of firing heavy cannonballs or shells but required enormous transport and logistical support to operate. They lacked mobility and thus were rarely useful in more mobile warfare situations. They have been generally superseded by strategic bomber aircraft and surface-to-surface missiles in modern warfare.

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