The vast, black sand beach on the north shore of Kauai, the largest island in Hawaii, is something of a hidden gem. However, while Kauapea Beach, a.k.a. Secret Beach, experiences nice average temperatures during the summer months, sunseekers should note that the nearby Kilauea volcano is one of the most active, and most destructive, in the world. And pretty sure that no sunscreen would prevent that you get burned!