"This spa belongs to Kona Kai , the marina-front, bayside hotel on Shelter Island (more like Shelter Peninsula). The subterranean spot isn't super over-the-top, but it's serene and warm, and it gets the job done. quality in treatments and aptly named "Zen Den" deliver on a high level. Try an Ayurvedic oil massage or a Javanese massage with a cooling yogurt rub." - Archana Ram