Cousteau rated this one of the top ten dive sites in the world. Volcanic archways, sheer walls and Rikoriko, the largest sea…Cousteau rated this one of the top ten dive sites in the world. Volcanic archways, sheer walls and Rikoriko, the largest sea cave by volume on earth, big enough to take a ship inside, with an acoustic that has been used to record albums. Bronze whaler sharks, stingray congregations, and a subtropical/temperate species mix found nowhere else. A remnant volcanic caldera, uninhabited since a massacre drove out the Māori population in 1820 and now a strict nature reserve; all fishing was banned in 1998 and the fish biomass has since exploded. The name came from Captain Cook in 1769. Anchorage: No landing permitted on the islands; day anchoring in the bays, exposed to swell. Hazards: No site-specific hazards noted, brief normally. More