4000 Mills Rose island

Rose Island — the self-declared micro-nation built on a platform in the Adriatic by Italian engineer Giorgio Rosa in 1968 — lasted roughly ten months before the Italian government sent the navy to demolish it. Rome had refused to recognize its sovereignty, partly fearing it would become a tax haven, and partly because the whole episode was an embarrassment. The story remained obscure for decades until a 2020 Netflix film brought it back into public consciousness, which almost certainly explains why this issue exists at all.