Inside a Kopeka Bird Cave, Atiu Island, Cook Island, Polynesia, South Pacific Ocean (photo)

Atiu Island, Cook Island, Polynesia, South Pacific Ocean. Inside the impressive Kopeka Birds Caves in Atiu. The caves of Atiu show obvious signs of being caved out by the fresh water that flows off the volcanic acidic soil of Atiu and through the Makatea. With each change in sea level, tunnels are carved out at that level to allow the fresh water though. A present day example of this is the Tiroto Tunnel. There is another tunnel like this in Tengatangi district that can only be accessed from the sea. The caves listed here are caves that were carved out when the sea level was higher. Anataketake cave in particular is the home of the kopeka. A bird unique to Atiu, which is able to echo-locate in the dark cave to find its nest. Tiroto Tunnel connects Atiu's lake to the sea. It is possible to wade down this tunnel almost to the sea. The last part of the tunnel is underwater. The flow moves backwards and forwards with the wave action and there is clean white sand underfoot. Wading this tunnel is an adventure. It is sometimes called the mud tunnel. Rima Rau burial cave: 'Rima' is five and 'Rau' is two hundred in the Atiu language. So Rima Rau means one thousand dead. There are many legends about who's bones lie in the cave. One legend tells of a famous battle, another a of cannibal feast, and yet another a story of revenge. Photographed in 2013