What killed the dinosaurs?

Uncover a mystery 66 million years in the making.

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Scientists have called it the K-T event (or Cretaceous-Tertiary extinction event), when entire species of reptile-like dinosaurs, which had lived on Earth for 230 million years, vanished. Researchers agree that this mysterious event happened around 66 million years ago, but they remain undecided as to the reasons why.

The Alvarez Hypothesis

The theory that has been most popular over the years is called the Alvarez Hypothesis, which argues that a meteor the size of a mountain collided with the Earth 66 million years ago. The collision released a huge amount of dust and debris, which blocked out the Sun and caused temperatures to plunge below freezing. This led to the extinction of non-avian dinosaurs (dinos not related to birds), and many other species.