One of the largest sea caves in the world, an entrance nearly 40m high in the cliff, opening into a chamber that runs back a…One of the largest sea caves in the world, an entrance nearly 40m high in the cliff, opening into a chamber that runs back a quarter of a mile into the island, with lichen and algae staining the rock the colours it is named for and sea lions barking somewhere in the dark at the back. Charted in the nineteenth century and known to the Chumash long before, the cave has been part of Channel Islands National Park since 1980. The Chumash occupied Santa Cruz for thousands of years and their villages ringed this coast. Anchorage: No anchorage at the cave. Lie at Cueva Valdez or Prisoners Harbor and run along in a tender when it is calm. Hazards: Do not take a yacht inside. Swell reflects off the walls, the ceiling comes down at the back, and sea lions breed inside in spring, when the noise alone tells you to stay out. Only enter with a flat sea and a way back out. More