Topographical Treats
At various times in the past - with sea levels fluctuating by as much as 150m with the advance and retreat of the polar ice-caps - these islands have been under water, battered by storms, covered with marine growths, visited by creatures long extinct.
Think of that when you clamber up the trail to Sailing Boat Rock, on Island No. 8, for example. As you squeeze through the crevices and archways, imagine them covered with colourful corals, sponges and algae. Where today you find birds and butterflies and squirrels, at one time dense schools, bright streams of fish instead commuted this way and that, with bigger fish and marine dinosaurs cruising through on the hunt.
A variety of forces have given shape to these islands. To begin with, the Similans were intrusions, upwellings of hot magma that found their way through weak spots in the Earth's crust 100-150 million years ago, working their way through thick layers of sedimentary rock already laid down at least 100 million years earlier still. Then, unimaginably powerful movements in the crust cracked the granite substratum into blocks, preparing the way for experiments in sculptural form by wind and wave.