TIL that the shortest war in history took place between Britain and Zanzibar on August 27, 1896, lasting only 38 minutes. The conflict arose due to a succession dispute within the Zanzibar Sultanate after the death of the ruling Sultan. As tensions escalated, the British government intervened and issued an ultimatum to the rival claimant, demanding his resignation.
When the ultimatum expired, the British fleet, consisting of warships armed with powerful artillery, swiftly attacked the Sultan's palace. The poorly equipped defenders of the Sultanate, outnumbered and outgunned, stood little chance against the onslaught. Within less than an hour, the Sultan's forces surrendered, and the British installed their preferred candidate as the new Sultan.
In 1982, the United States Border Patrol set up a roadblock and inspection point on US 1 just north of the merger of Monroe County Road 905A/Miami-Dade County Road 905A onto US 1 (they are the only two roads connecting the Florida Keys with the mainland), in front of the Last Chance Saloon just south of Florida City. Vehicles were stopped and searched for narcotics and illegal immigrants. The Key West City Council complained repeatedly about the inconvenience for travelers to and from Key West, claiming that it hurt the Keys' important tourism industry. Eastern Air Lines, which had a hub at Miami International Airport, saw a window of opportunity when the roadblocks were established; Eastern was at the time the only airline to establish jet service to Key West International Airport, counting on travelers from Key West to Miami preferring to fly rather than to wait for police to search their vehicles.
When the city council's complaints went unanswered by the U.S. federal government and attempts to get an injunction against the roadblock failed in court, as a form of protest Mayor Dennis Wardlow and the council declared Key West's independence on April 23, 1982. In the eyes of the council, since the U.S. federal government had set up the equivalent of a border station as if they were a foreign nation, they might as well become one. As many of the local citizens were referred to as Conchs, the micronation took the name of the Conch Republic.
As part of the protest, Mayor Wardlow was proclaimed prime minister of the republic, which immediately declared war against the United States (symbolically breaking a loaf of stale Cuban bread over the head of a man dressed in a naval uniform), quickly surrendered after one minute (to the man in the uniform), and applied for one billion dollars in foreign aid.
Here is a neat video by Geographics that covers it