Over time, our planet has been shaped by many monumental events.
From the Cambrian explosion of life some 540 million years ago, when most animal forms appeared, to the rise and fall of the dinosaurs, the dramatic course of biological evolution is well documented in the fossil record.
But the Earth has also lived through largely obscure and little-known geological eras.
In this video, we want to tell you about a long period that is almost completely devoid of fossil evidence.
This is not because we cannot find the rocks in which life might have left its footprints, but because throughout billions of years, all geological and biological processes seemed to have ceased or greatly diminished.
A billion years is a long time, even on a geological scale-it's more than one-fifth the age of the Earth-where did it end? How is it possible that we know so little about it?
Well, we can't give away any spoilers, but you should know that we're talking about a billion-year period that began in the middle of the Proterozoic Era.
How can we define it? A period of darkness, a black hole in history? The missing chapter in Mother Earth's great book?
We don't need to worry about it. Someone before us has already thought of calling it what it deserves to be called...
But how?
Well, to find out, just keep watching the video!