Today, piles of curious stones, some of them as big as houses, lie as though collected and later abandoned in careless heaps by some ancient race of beachcombing giants. Even Sailing Boat Rock, the distinctive formation teetering high above the cove on Koh Similan (Island No.8), has been shaped in this way.
And boulders just like these spill in jumbled piles down beneath the surface of the sea to 35m and beyond, where submarine peaks, canyons, caves and passageways provide scuba divers with some of the most interesting submarine prospects in the world. (On the west side of the islands, currents have kept the formations clear of sand; on the coral-covered sandy slopes of the east side, the boulders have been largely buried.)