Mitiaro, the fourth island in the Cook Islands group,'s of volcanic origin. Standing in water 14,750 feet deep (4500 m) it's four miles (6.4 km) across at its widest point. It's surrounded by the belt of fossilised coral—makatea—between 20 and 40 feet high (6 to 9 m) characteristic of islands in the southern group. The centre's almost flat, quite swampy and contains two freshwater lakes teeming with eels and the imported tilapia from Africa where it's known as bream. Beaches are lim… (More on Mitiaro)