[Cboldt]

-- but your link is showing a garden feature, not an architectural/city layout feature. Is the info in your link reflecting the same rationale for both? --

No. My link is an independent reference that uses the word "keyhole."

[TEXOKIE]

To summarize on “KEYHOLE”:

Ok so we have two independent references pertaining to Vatican. City layout features noticed by NIKK...

and the one you found, Cboldt, from which “keyhole” allows views from Knights of Malta property - at least one of which is a garden feature looking like a keyhole from which one can view Vatican dome.

Plus we now have reference to satellite equipment known as “keyhole” per Early Bird.

If I scrambled who found what, please forgive me. Still way behind!