While correct, it is truly amazing, 'The Grotto' is not well known by many. We discovered it years ago while on scuba at Mountain Point. It is possible to see a small blue circle on Google maps, at the end of the first chute on the right. It is simple enough to snorkel all the way down the cute, which seems to dead end. At the very end simply look down and forward and you will see an arch with some light coming through. While the little grotto is amazing, it could be dangerous for an inexperienced swimmer. From memory, the opening under the arch is plenty large for swimming through. It will require the snorkeler to confidently dive down to about six feet and swim perhaps fifteen feet under water before surfacing inside the grotto. I feel an inexperienced or weak snorkeler/swimmer should NOT attempt it. Those that feel comfortable with their ability should probably have fins on their feet, to help them down and through the arch. Yes, it should be a calm day.