While brown eyes may be the most common around the world, blue eyes are the second most popular. But the story behind this unique trait is anything but ordinary. In fact, evidence suggests that all blue-eyed individuals can be traced back to a single ancestor who lived between 6,000 to 10,000 years ago.

That’s right – every single person blessed with those mesmerizing azure orbs shares a common genetic mutation that “turned off” the ability to produce brown pigment in the iris. This ancient switch has left blue-eyed folks with some surprising advantages…and disadvantages.

One of the most well-known quirks of blue eyes is an increased sensitivity to light. While those with darker irises have more melanin to protect the delicate tissues at the back of the eye, blue-eyed individuals lack this natural shield.