Vatican city is a sovereign state within the city of Rome. It became a state in 1929. Its size is only 110 acres, the smallest country in world. It’s the size of a typical small residential ranch in Texas.
And I tell you, you are Peter and on this rock I will build my church and the gates of Hades will not prevail against it. Matthew 16:18
There are two security forces that protect the Vatican City State;
The Corps of Gendarmerie of Vatican City handles border control and criminal investigations.
And the Swiss Guard, trained in Switzerland, is the personal security force of the Pope. The Vatican's gold and wealth is in Switzerland.