If you think about this subject objectively, you might start to think about the SEVERAL races of Homo Erectus who have lived on this planet. You might also think about the fact that every single culture on this planet has had myths and legends about a faery race.
Now make it simple and think about the Neanderthal race - where did they go ? The answer is - nowhere. They blended with the race they shared the planet with - the Cro Magnon. Look around you. You will see many people bearing Neanderthal characteristics. Now think back to where I started. If there was a faery race, where did they go ? Same answer- nowhere ! They are merged with us and are part of our DNA. Again, look around you !
Simplest answers are always the best
