Thrombolites

Thrombolites are not actually "rocks," but ancient forms of microbial communities that photosynthesize (produce energy from sunlight).
They obtain calcium carbonate from the water to form these structures, which are about 2000 years old and visible at high and low tide.

600 million years ago, the ancestors of thrombolites and stromatolites produced the oxygen needed for life on land to exist.
Today, they can only be found in a few places in Western Australia and elsewhere in the world.

I still can't quite wrap my mind around the fact that these are living organisms.

* Special thanks to Phil for the video footageRead more