Refreshed: I'm sure there are many variants on the same theme, and at least a few of them forgeries by some imaginative and over-zealous photographers. The photo I saw was exclusively aerial, so evidently not the same image as the one belonging to your uncle. It was also quite blurred and impossible to judge scale, coz there was nothing else in the image against which to gauge it.
Agreed re. Freemasonry - it's just one of many corruptions of Christianity. The Gnosticism that plagued the early church is arguably its antecedent. You don't hear so much about Rosicrucians these days. I wonder where they've all gone?