Vatican City State is .17 square mile.
The Catacombs of Rome are an estimated
375 miles, which are under the jurisdiction
of the Holy See.

Also, despite losing the Papal States in the
1870's, the Holy See is the 3rd largest
landowner in the world.
[link to www.businessinsider.com]

True value of its priceless buildings, art,
relics ? just that. priceless.