Moeraki Boulder Beach, New Zealand

Thirty km south of Oamaru, on the South Island's east coast, is a stretch of beach with ancient boulders that have a peculiar geological orgin. These are perfectly spherical and lie haphazardly scattered about the beach. They are concretions--a kind of rock originally formed in deep sea floor sediment in a process similar to pearl formation where materials fuse around an original nucleus. Fossilized shell, bone fragment and animal skeletons have been found as the core of these rocks. At a later geological date, these deep sea concretions were then uplifted in a landmass that formed the cliffs surrounding the beach, and over time, as the cliff eroded, the boulders were released and ended up on the beach. Erosion of the boulders has exposed a network of veins that makes them look like giant turtle shells and indeed, standing on the beach, you find yourself half expecting them to get up and move. Pied oystercatchers were everywhere along the beach.