The pretend Vatican State at the UN
The Vatican is by far the smallest State in the world, being just over a hundred acres in size. It plays at being a real State by issuing its own stamps, but it has no proper citizens (just transient employees of the Catholic Church), few public services (Italy provides it with police and water) and no real economy (though it does have a novelty ATM machine that issues instructions in Latin).
But that does not matter, because the toy Vatican State does not generally interact with other real States. Instead, an entity called the Holy See, which is the central government of the worldwide Catholic Church, masquerades as a State and deals with actual States from its base in the Vatican.
This distinction is very important. It is the openly religious Holy See, and not the theoretically civic Vatican State, that swaps diplomats with actual States, and that has Permanent Observer status at the United Nations and other bodies. But the Holy See does not have any citizens, or any defined territory, and all that it governs is the religious affairs of some citizens of actual civic States…