The Principality of Sealand is a micronation that claims HM Fort Roughs (also known as Roughs Tower), an offshore platform in the North Sea approximately 12 kilometres (7.5 mi) off the coast of Suffolk, as its territory. Since 1967, the decommissioned Roughs Tower has been occupied and claimed as a sovereign state by the family and associates of Paddy Roy Bates. Bates seized Roughs Tower from a group of pirate radio broadcasters in 1967 with the intention of setting up his own station there. Sealand was invaded by mercenaries in 1978, but was able to repel the attack. While Sealand has been described as the world's smallest country, it sits within British territorial waters and is not officially recognised by any established sovereign state.

Vatican City, officially the Vatican City State, is the Holy See's independent city state, an enclave within Rome, Italy. The Vatican City State, also known as The Vatican, became independent from Italy with the Lateran Treaty (1929). With an area of 49 (121 acres) and a population of about 825, it is the smallest sovereign state in the world by both area and population.