Open Ceiling Cave on Na Pali Coast, Kauai, Hawaii, USA. This cave is a hollowed-out lava tube, and may have served as a place where ancient Hawaiians could rest in their canoes when traveling along the coast. Photo by threeifbysea (Instagram)
Papakōlea Beach (also known as Green Sand Beach or Mahana Beach) is a green sand beach located near South Point, in the Kaʻū district of the island of Hawaiʻi. One of only two green sand beaches in the World, the other being in Galapagos Islands. It gets its distinctive coloring from the mineral olivine, found in the enclosing cinder cone.