Despite its apparent simplicity, a tube-like body topped with tentacles, the sea anemone is actually a highly complex creature. Scientists from the Institut Pasteur, in collaboration with the CNRS, have just discovered over 100 cell types in this small marine invertebrate as well as incredible neuronal diversity. This surprising complexity was revealed when the researchers built a real cell atlas of the animal. Their findings, which will add to discussions on how cells have diversified and developed into organs during evolution, have been published in the journal Cell.