Principality of Sealand
One of the few micronations to control a physical location, the Principality of Sealand has existed de facto since 1967 on an abandoned British anti-aircraft gun tower in the North Sea. At the point when it was taken over, the tower had been abandoned by the Royal Navy and was outside British territorial waters. Paddy Roy Bates, who styled himself Prince, claimed that it was "terra nullius". Despite rejecting this claim on the basis that the tower is an artificial structure, the British government has never attempted to evict the Sealanders, and a court in 1968 confirmed that at that point, the tower was outside British jurisdiction.