No matter how much research has been done in the field of genetics, we will likely never really know everything about it. We seek out partners with certain traits so they can passed on to our children, but there's no way of telling exactly what they will look like once they're born.
Eye color seems to be one of the most talked about genetic traits, after all eyes are usually the first thing you notice on a person and can reveal a lot about them.
While we're used to the combination of blue eyes with blonde hair or brunettes with brown eyes, every so often we come across a striking eye color that stops us dead in our tracks.
Of course, beauty is subjective so it certainly isn't easy to rank the world's most beautiful eyes, but the following 7 would definitely make the cut.
Green is the rarest eye color in the world. It is estimated that only 2% of the world's population have green eyes. This is probably one of the reasons why the simple yet striking "Afghan Girl" photo captured by journalist Steve McCurry in 1984 caught the world's attention like no other.
Click on the next page for more photos of the world's most beautiful eyes.
They say beauty is in the eye of the beholder but there's no denying that some people have been blessed with gorgeous eye colors, from brown to blue and green, some eyes just stand out from the rest.
One of the rarest combination is the world is blue eyes and dark skin, it may sound made up but it actually occurs in a small percentage of the population. According to research, blue eyes in Africans and African-Americans is due to an ancient genetic mutation or a result of an eye pigment condition known as ocular albinism.
Actor Michael Ealy is a famous example of such a rare mutation.
As for the rarest combination of them all? Red hair and blue eyes. Most redheads have brown, green or hazel eye colors, but if both parents carry the red hair and blue eyes recessive genes then a child could be born with the unique look.
What's your favorite eye color? Let us know in the comments!