Hawaii’s black sand beaches are formed by lava which hardens into black rock, and later shatters to create black sand. One of my favorite black sand beaches is Waianapanapa State Park in Maui, on the road to Hana. There is a beach where you can swim, and elevated rock areas where you can hike and see the beautiful beach from different views. I especially love the sea cave formed from lava rock, with cool, calm air inside.