Our remote ancestors likely had dark eyes, whether brown or black. Blue eyes are common in northern Europe and likely emerged some 5,000 years ago. This suggests that genetic evolution can be more ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

Your eyes aren’t just a pretty feature of your face. They can provide surprising insights into your personality, your health ...