Dinosaur Extinction: Massive Extinctions

Since the first animal fossil register, approximately 800 million years ago, the Earth has suffered at least twelve massive extinctions, of which five were of truly gigantic proportions.
Millions of species disappeared forever in these periods of massive deaths, but always some plants and animals remained as a point of departure for renewed diversification. 
When we hear of extinctions in pre-history, we tend to think of the time when the Earth was inhabited by fabulous animals: the dinosaurs. 

The dinosaurs dominated the zoology of our planet for one hundred and forty million years, a period which, in comparison with the history of our species, makes them almost eternal. But the dinosaurs only dominated the world for a brief period of time if we compare it with the age of the Earth. Even so, they are a fascinating example of the fragility of life. Because, even though they were the most formidable, powerful beings that have ever lived on our planet, they could do nothing against the forces of the cosmos.

A force almost impossible to imagine came from space.

A medium-sized meteorite crashed into the Earth. It was neither the largest nor the most devastating of the many that have impacted against our planet, but the power of the impact was the equivalent of 10,000 times the detonation of all the nuclear weapons in the world.
The forests burnt, adding smoke to the dust raised by the impact and the eruptions of thousands of volcanoes.
The sky was covered over, preventing the sun from getting through. The climate changed radically. Without light, many plants died, and without food the great colossuses of our history disappeared from the Earth forever.
But this tragedy of the Cretaceous era was neither the first, nor the most devastating massive extinction.
A volcanic crater in the interior of the jungles of Costa Rica provides a clue to what the greatest murderers of pre-history were like.

CC BY-NC-ND 2.0) Yo Mero - Lluvia-de-meteoritos