This episode is dedicated to our four-legged best friends: dogs and cats. We will see how their destiny intersected with the history of man starting from prehistory. Let's discover how and why the dog has transformed over the centuries and how its extraordinary qualities have made it the animal most faithful to man. We show you the work of guide dog trainers for the blind. Alberto Angela tells us the odyssey of Laika, the cosmonaut dog, the first living being to reach space. From archaeological findings in Egypt, it has been discovered that the cat was considered a deity and mummified after death as was done for nobles and Pharaohs. Superstitions and ancient beliefs have spared neither dogs nor cats. In fact, cats, especially black ones, have often been considered evil creatures in the West, and therefore persecuted. And they weren't the only ones: owls, owls and other nocturnal birds suffered the same fate.