LOL, 250 million tons of magnetized basalt logs weighing up to 50 tons each used as the sole architectural material in a complex bigger than Giza on an island without fresh water containing manufactured tunnels to other islands - and none of the engineering requirements of its creation has been explained, especially supposedly by natives living in grass huts and transporting themselves in canoes.
No mystery here?
Whatever.
There’s no water supply at Nan Madol; the island itself has water, which means the water had to be fetched. With a complex that took that much work to build, that the authority there could have water and food brought from the mainland isn’t that farfetched. The rumors about tunnels running from the complex are likely of the same source as the flying dragon, giant platinum coffins, and black magic. Not surprisingly, efforts to find said tunnels have all failed.