Principality of Sealand
The Principality of Sealand, a micronation founded on a former World War II fort in the North Sea, has issued a number of coins and stamps for collectors. These coins and stamps are denominated in "Sealand dollars" (SX$). Sealand coins can be considered souvenirs only or "rounds" since they do not circulate anywhere and are not accepted as currency by any nation.