I believe they weren't aware of the nature of the earth. They didn't know anything about the geosphere, and thought there was an opening in the poles. I think it's no different than masons trying to locate Atlantis, which despite thousands of years looking, still haven't found anything. This hollow earth nonsense has been resurfacing again, and of course is proven wrong by that fact that we know what's inside of the earth. If it was hollow, there wouldn't be a core, which in turn earth would be without a magnetic field, and some will say " well Jupiter doesn't have a solid core and is technically "hollow" and it has a magnetic field" but that's due to Jupiter being a gas giant and about a third of they way down into jupiter the hydrogen becomes compressed and metallic, and due to the fast rotation creates a magnetic field. As far as Atlantis is concerned, IMO it's an allegory, the perfect model of a society. If there's any actuality to Atlantis, I think if it is anywhere, it's north America. There is evidence that the Greeks and Egyptians travelled to the new world 1000's of years before the Europeans. There is proof in some mummies who have traces of tobacco and cocaine in their systems, which in the ancient Mayan and Aztecs used in religious ceremonies ( kinda reminds me of DMT in acacia you've mentioned before). Some more evidence is that you don't even need to cross the oceans, one just need to sail along the coastlines. Out of gibraltar one can sail up, hugging the coast of portugal, and Spain, all the way up to Britain, still not losing sight of coastline, on to Greenland and south to Newfoundland and the rest of the new world. It's not impossible to do. This is touched on in Uriel's machine, by Christopher night and Robert lomas, who wrote the Hiram key series, and also other scholars have studied and somewhat proven this.