This series focuses on Earth's oceans, from coral reefs to the coasts. Along the way, we are introduced to a number of sea creatures, large and small, that dwell in these precious environments.
We don't know exactly how and when life began on Earth, but the answer probably lies in the depths of the ocean: It is here that the first unicellular organisms evolved.
How do coral reefs form, and what role do they play for underwater creatures such as fish? In this video, you can see some fascinating life forms and how they interact with one another.