The story of this place
At Hamelin Pool in Shark Bay, Western Australia, you can stand at the edge of a shallow, hypersaline lagoon and look at structures that are 3.5 billion years old. The stromatolites — dome-shaped microbial mats — are identical to the organisms that first produced oxygen and made complex life on Earth possible. Without their ancestors' work, there would be no air to breathe, no animals, no humans. They are, quite literally, the origin of everything.
Stromatolites grow at approximately one millimetre per year. The ones at Hamelin Pool have been growing for thousands of years and reach up to a metre in height. They only survive in hypersaline water because the salt deters the snails that would otherwise eat them. Shark Bay is the only place in the world where stromatolites live in fully marine conditions. The entire Shark Bay region became a UNESCO World Heritage Site in 1991 for having the world's largest seagrass meadows, dugong populations, and the stromatolites — some of the oldest life-forms on Earth still living.