Sovereign Order of Malta:: Palazzo Malta
The Order of Malta was originally create by the papal degree during the crusades as a military organization and was based in Italy, then Cyprus, then Rhodes, and then eventually Malta, before being expelled by the French, and eventually Rome. There are two land possessions in Rome that are considered extraterritorial within Italy, just like Vatican. Palazzo Malta aka Palazzo Magistrale is the official headquarters of the Order of Malta. You cant enter the building, but there is a small visitor center where you can technically step onto the country’s territory and buy stamps or coins.