The shortest war in history lasted only 38 minutes - Apparently.
The Anglo-Zanzibar War between the United Kingdom and Zanzibar on August 27, 1896, is recorded as the shortest war in history. The war began when the pro-British Sultan Hamad bin Thuwaini died, and a rival claimant, Khalid bin Bargash, seized power. The British issued an ultimatum, which Khalid refused to comply with, leading to a 12-gun naval bombardment of the city, which ended with Khalid's surrender after just 38 minutes. This brief conflict was sparked by a dispute over who should be the ruler of the island nation of Zanzibar.