The Moeraki Boulders, New Zealand
These large spherical stones, scattered along the beach 40km south of Omaru, are formed from ancient sea floor sediments around 60 million years ago. Scientists believe four million years of crystalisation gradually formed the boulders into the pearl-like structures that they are today. Maori legend holds that the boulders are gourds washed ashore from the great voyaging canoe Araiteuru when it became shipwrecked. Each boulder weighs several tonnes and stands up to two metres high.