A lovely state park stretches along the rugged volcanic shoreline on Maui's west side, three miles from Hana. A 2.2-mile out-and-back hike starts at the black-sand beach and follows the dramatic coast. Explore lava tubes, photograph rock arches, and witness blowholes sending plumes of seawater into the sky. Avoid standing too close to these geysers—as well as the lava benches near the ocean, which can crumble—and watch for high surf. Want to cool off after the trek? Take the loop trail to the park's freshwater caves. Pack an underwater light to explore the two chambers (the first tends to be more clear and inviting).