These caves shouldn't exist. Or, at the very least, we can't yet explain them.

The whole premise of the video is that there is currently no definitive/conclusive explanation, because no serious archeological study on these caves has occurred yet, and so there are no Wikipedia links to share (at least that I could find). And even targeted keyword searches don't turn up much. About the only credible thing I could find is an older article (and related study) about various bits of similar archeological evidence on some of the islands, and in one of the other caves mentioned in the video:

https://portuguese-american-journal.com/carthaginian-temples-found-azores/
http://www.apia.pt/doc.php?co=118&in=0

So, regardless of your YouTube aversion, I would still highly recommend just watching the video. The YouTuber behind the channel, Evan Hadfield (son of the astronaut), is an exceptional speaker. He's basically the Canadian version of Tom Scott, albeit often focused on far more serious history, anthropology, archeology, sociology, and political topics.

Interesting article (and person). I recognize Buckminster Fuller's name from having heard it in relation to his architectural designs (e.g. the geodesic dome in Montreal), but honestly didn't know much else about him. Thanks for sharing.

p.s. Since I was also curious about Critical Path, here's the relevant excerpt which I think you're referencing:

Eratosthenes, in 200 B.C., measuringly calculated the circumference of Earth within 1.5-percent accuracy. He also made a map of the world running from clearly identifiable England on the northwest to the (not so convincingly identified) mouth of the Ganges in the southeast. His map included all of Africa on the south (with a reasonably accurate foreshortened profiling of South Africa, which outline could not have been included by him had not such an around-Africa-voyaging been already accomplished and reported).

It was also around 200 b.c. — as we learned authoritatively only five years ago — that the Phoenicians sailed from the Aegean Sea to both the east and west coasts of South America. Because of the prevailing winds the west coast of South America would be much more naturally reached from the Mediterranean by first sailing southward, rounding the southern tip of Africa, crossing the Indian Ocean northeastwardly on its main current to pass just north of Australia, then turning northward with the Japan Current and the prevailing winds to transit China, Japan, and the Aleutian Islands to Alaska, and then on the same current southwardly to the west coasts of both North and South America, where the most recent deciphering of the prephonetic Phoenician code makes clear that the Phoenicians had landed. Locally documented in stone carving, this occurred circa 200 B.c. — ergo, was contemporary with Eratosthenes’ map-making. Then, after stopping on the west coast of South America, the Phoenicians probably followed the coast southward until the “Roaring Forties” winds and current swept them around the Horn into the South Atlantic, whence the northerly current took them along South America’s east coast. Here they made another stone-carving-recorded stop. Thereafter the Atlantic Gulf Stream swept them north-
wardly, then westwardly, along the northern coast of South America, through the Lesser and Greater Antilles, all the way westward to the Panama Isthmus, then north from Yucatan into the Gulf of Mexico, then southward north of Cuba around Florida, then with the Gulf Stream, diverted northward by the Virgin and Bahama islands into the swiftly flowing North Atlantic Gulf Stream, past Cape Hatteras, Nova Scotia, south of Greenland, Iceland, and Spitzbergen, where the ice forced them to go westward until they discovered their familiar Scandinavia, British Isles, etc., from which they returned home to the Mediterranean and to Carthage on the north coast of Africa or to their capital port of Biblos on the eastern Mediterranean shore.

I feel confident that Eratosthenes had knowledge of their circumnavigation. Without a magnetic compass, sextant, or chronometer the Phoenicians were guided only by their familiarity with star constellations and driven by prevailing ocean currents, trade winds, and angular-pattern-informative-following-of-coastlines. They kept recorded accounts of all changes in their course angularly as plotted against the star pattern and of the whole sky.

The Phoenicians obviously had to subsist on fish and rainwater.

As a sailor-navigator myself, I am confident that Eratosthenes would not have closed his map along its top edge if he had no knowledge of the fact that the Earth had been circumnavigated. The almost-closed, circular bay shown along the top edge of his map, which showed that such an experience occurred midway on the trips, is probably occasioned by the fact that the South and North Atlantic Gulf Stream sweeps deeply into the Caribbean Sea all the way to the isthmus of Panama and then through the Gulf of Mexico, as already recounted. (See Figs. 8 and 9.)

Around the same year, 200 b.c., the Stoic philosopher Crates developed the first terrestrial globe — celestial globes preceded it.

Source: https://archive.org/download/LIBRORBuckminsterFullerCriticalPath/LIBRO_R_Buckminster_Fuller_Critical_Path.pdf
(figures mentioned in the above, from pg 34-35, are on pg 36 and 38-39)