From Morocco. Stromatolites display fascinating glimpses into the history of life on earth. They are found in rocks over 3 billion years old and the patterns you see were formed by cyanobacteria. Today, we know this as green algae. Collectively, they contributed to the oxygen in our atmosphere. Stromatolites are a type of Algal Mat, which is made up of layers of green algae. This layer builds up over time and forms the structure that we see today. The amazing thing about these structures is that they provide an insight into how life has evolved on earth; they show us how life can adapt to changes in its environment and what could happen if our planet’s climate continues to change at such a rapid pace.