Kaimu was the most beautiful black-sand beach in Hawaii until the 1990 lava flow that consumed Kalapana torched its stately palms and filled the bay with pahoehoe (smooth-flowing lava). Now, a 0.3-mile walk along a striking red-cinder path takes you to a tiny cove where black sand accumulates and dissipates as nearby lava flows battle the forces of erosion. Residents have planted hundreds of palm seedlings in hopes of returning the land to its former glory. Swimming is unwise, but it's gorgeous.
On your walk out, look for the Hawaii Star Visitors Sanctuary, the world's second official UFO landing pad, dedicated in 2014. The founders hope that the piles of rocks and small shrines will entice extraterrestrials to land here and establish diplomatic relations with the peaceful Kingdom of Hawaiʻi.