The Gold of the Gods by Erich Von Daniken

Found this book in an old book store, published in 1973, the pages were falling apart, had to tape them together.
The author of the book goes on to explain his theory of the origin of man kind and how homo sapiens evolved.

You have to keep an open mind reading this book. His theory is that super intelligent entities came to our planet and created an intelligent specie that we call humans.
His evidence is based on his travel all around the world and studying the ancient artefacts and sites and found that they all had things in common...for instance, statues with helmets which he describes as space helmets and artefacts shaped like planes which the legends described as dragons and flying snakes.

I highly recommend the book if you would like to study the details of his research and theory.