It's mostly unknown in the popular consciousness. To the extent Americans know or connect to anything about old world history and places, it's basically western Europe, which includes the Romans and Greeks due to the Renaissance. (I think it's kind of a fossilized older English conception of the world, but there's lots of factors.) Plenty of exceptions, of course, where people also belong to another culture, in whole or in part, or have developed an interest elsewhere, but in general anything east of Germany or south of the Mediterranean is basically unknown. (It's not surprising; people know their own culture and maybe something about nearby or widespread ones. And nothing else is particularly nearby in the Americas.)
So if you're going to talk to lay people about ancient structures, you're going to talk Rome, or maybe some cathedrals, because otherwise you're not talking about the mechanics of ancient structures, you're talking about appreciation of otherwise unknown architecture, and that's not the same thing.