Earth may be known as the Blue Planet now, but evidence suggests that back in the day, it was probably pink.

Scientists have discovered the earliest evidence for a colour appearing in nature: bright pink pigments that exist in an ancient kind of chlorophyll, said Nur Gueneli, a researcher with the Australian National University. Discovered inside rocks found under the Sahara Desert in West Africa, these pigments are believed to be over 1.1 billion years old, Interesting Engineering reported.

While the chlorophyll we learn about in science classes today is green, this prehistoric version was used by marine bacteria that cast a ‘brilliant pink’ colour over the ocean all those years ago. That hue wouldn’t be overtaken by greener algae for hundreds of millions of years.

Those algae eventually turned into the basis for the wide variety of life that led to the evolution of large animals, including humans. But a billion years ago, “the planet belonged to the bacteria”, Live Science reported.