The Amazon rain forest. Scientists believe it holds thousands of species of plants, animals and insects we have yet to identify. And at least 50 tribes who have still not had contact with the outside world.

But before it could become the marvel it is today, the rain forest had to burn to the ground.

That big burn was caused by the same asteroid that wiped out the dinosaurs.

Scientists have studied Amazonian fossil plants from a few million years before and after the asteroid to reconstruct the story. It looks like this:

70 million years ago, the Amazon basin was lightly covered in conifers and ferns.

Large herbivorous dinosaurs ate huge volumes of plants and trampled others, keeping the forest in check.

Then the asteroid struck, sending a shockwave of fiery winds that flattened and incinerated the Amazon forest.

When the skies cleared, greenhouse gases from the blast and fires trapped more heat in the atmosphere.

In this new, warmer environment, the same conifers and ferns didn’t regrow. This left the Amazon basin open for new competitors: flowering plants.

Over a few million years, these evolved into thousands of species, from the towering broad-leaf trees that dominate the rain forest today to the many smaller plants that live in their shadows.

We know the Amazon as the most biodiverse place on Earth. But it never could have gotten there without the asteroid that cleared out the old to make way for the new.