A subject of much myth and legend, not to mention an awesome spectacle, this natural landmark is definitely a must see, but only from a distance. While modern geologists have determined that the fierce saltwater sprays and otherworldly sounds that issue from the Horn are the result of air moving through lava tubes, the ancient Hawaiians chalked it up to an ancient dragon-and-warrior tale. Note: As with any other blowhole, it is imperative that you always keep a safe distance from the rocks and the ocean.