After WWII, several British gun platforms were abandoned in the English Channel.
In 1967, a pirate radio broadcaster took up residence in one of them and declared the fort an independent nation, and after a run-in with the Royal Navy a court ruled that Sealand was outside British jurisdiction.
The Seaside Restaurant is called Grotta Palazzese Hotel and is one of the most magical places to eat in the world. It's in Polignano a Mare, Italy's coast!