calling all historians...what monument is depicted herein?

Just a quick glance seems to make me think it comes from Cooperstown, NY.

Oooh! Check out APB’s response!

I think that’s it!

Threadspotting?

There is an actual small round temple like this is Rome, near the Ponto Roto. If the ROmans were into garden follys, this would be one. The “Temple of Hercules” has about 16 pillars in a circle around the center building. The Greeks were not into domes and circular buildings so much as rectangles and triangular trusses.