120-acre Waianapanapa State Park is a great place for snorkeling and swimming on a black-sand beach. With black-as-night lava jutting out into the deep blue sea, the sights here are breathtaking. But enter the water only on calm days; when the surf is strong, the sandy shore drifts away quickly. The park is great for picnicking and exploring nearby caves, but keep an eye on your children and keep them away from wet and slippery places.
There is a well-marked trail leading to Waianapanapa Caves, two small indentations that look like oversize bathtubs. An old Hawaiian legend tells of Popoalaea, a beautiful princess who ran away from Kakae, her mean husband, and hid in these caves. When Kakae found her, he was so angry that he viciously killed her there. Hawaiians say the waters periodically turn bright red in memory of the ancient bloodshed. Scientists, however, have reported that the red tinge in the water is caused by several thousand tiny red shrimp that drift this way during various weather and wind patterns.