'Stromatolites at dawn' by Frans Lanting: Low tide at sunrise exposes the cracked domes of stromatolites lining the shore of Australia’s Shark Bay. These are living structures. The surfaces are the newest layers of sediment formed by communities of cyanobacteria. As early as three billion years ago, the ancestors of these micro-organisms began to release the oxygen that altered the Earth’s atmosphere and created conditions favourable for the evolution of complex life, and that includes us. Photographing them under the spreading pink clouds of sunrise hints at that remarkable change in the air. For many years, the only pictures of stromatolites were made by geologists for textbooks.
http://en.wikipedia.org/wiki/Stromatolite