About 17 kilometres west of Krabi Town, Susan Hoi — the Shell Cemetery — is a broad flat shelf of rock extending into the sea, formed entirely from the compressed and fossilised shells of freshwater snails. The formation is 75 million years old and is one of only three such sites in the world; the others are in the United States and Japan.
The rock shelf is open to walk on, and you can clearly make out the individual shell impressions set into the stone. At low tide the formation extends a considerable distance. The site is straightforward to reach by songthaew from the town centre; the journey takes about 30 minutes. There is a small museum and souvenir area at the entrance. It sounds like a modest attraction, and in some ways it is — but the scale of geological time involved in creating it gives it an odd, quiet power.