EDIT: What I said in this comment probably is not true. While the changes I made were added to the map, only users can create pokestops via a review process, apparently. Must have been a coincidence.
Niantic uses Open Streetmaps to create their pokestops. Somebody probably created a P.O.I. on the island based on a real statue or structure which an algorithm then automatically turned into a pokestop.
Source: I sometimes contribute to OSM and the additions I make often turn into pokestops a couple of weeks after, especially in remote areas without other P.O.I.s nearby.
No, I don’t play the game but am around people who do.