A massive "beehive" shaped cave, with collapsed roof, at Mercer Bay. This beach lies between Piha and Karekare on Auckland's west coast. Accessible only at dead low tide and calm seas, the caves are under the highest cliffs in the Auckland region. Scramble and climb down a 160m cliff to the beach, walk 100m through a pitch black, winding sea cave, out to the ocean. Now you're below a 240m cliff and by wading around to the north you find the entrance to the cave. Worth the effort.