Kauai Open-Ceiling Sea Cave
Also known as Pukalani, this sea cave is like a cauldron. Inside the cauldron the light of day shines down into the opening. Just to make this place even more fantastical, a small island rises out of the middle of the sea cave. The surrounding waters can be treacherous so swimming here is not recommended. However, find a boat tour navigated by an experienced local to take you into the heart of the sea cave for an experience most only dream about.