Reply #4: I was thinking about that...

[Solon]

My problem was the limit of 10 for a poll, I missed the many structures of the Americas, from Cahokia Mounds to the many temples of Latin America. Not to mention the temple complexes of Oceania and Polynesia, etc. If the poll was between 20 choices, I might have put those in, in addition to an "other" and "all of the above" option. But a point in my post is this, these are all technically world heritage sites, and there are good chances that many of our distance ancestors had a direct hand in the building of most of them. That, I think, is the point of my post.