This elaborate nativity scene is prominently displayed in downtown Coral Gables near the corner of Ponce De Leon and Alhambra, on a little circle of land that might be public, or might be an amenity belonging to a nearby office building. It has no sign on it saying who erected it or how it got to be there.
Google Maps actually has a good image of it:
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I've never taught or litigated an Establishment Clause case, but I was under the impression that if this is public land, there has to be a sign on such a display explaining who paid for it, lest it appear to be a city-purchased religious display. Then again, it might be private land. Indeed, one of my colleagues tells me that there used to be a church where the building next to the circle now stands (the tall thin building in the image above), and speculates that when they sold the land they held on to this piece (or kept an easement) just for this purpose. Could be: but why no sign claiming credit?