The shortest war in history lasted 38 minutes - Apparently.
The Anglo-Zanzibar War, fought between the United Kingdom and Zanzibar on August 27, 1896, holds the record for the shortest war in recorded history. The conflict began when Zanzibar's pro-British Sultan Hamad bin Thuwaini died, and the opposing faction installed a new sultan, who was opposed to British rule. The British issued an ultimatum, which was ignored, and a naval bombardment ensued, forcing Zanzibar to surrender just 38 minutes later. This brief conflict was sparked by a dispute over who should become the new ruler of Zanzibar.