[Origin of the white race..] Why are white people so diverse. Secrets of White Race Diversity

Most humans have only one hair color and one eye color, black hair, brown eyes, and brown skin. Europeans have a different color scheme, their hair being also brown, flaxen, golden, or red, and their eyes also blue, gray, hazel, or green. Finally, their skin is pale. This diversity reaches a maximum in an area centered on the East Baltic and covering northern and eastern Europe. Why this color diversity? And why only in Europe?

How did this unusual color scheme come about?