The color blue has only been around for so long, both literally and linguistically.
Homer's "The Odyssey" is full of details about clothing, animals and characters' faces but makes no mention of the color blue.
And although red, yellow and green are named, they're only mentioned a handful of times, which prompted philologist Lazarus Geiger to find out whether this phenomenon only occured in the Greek language, according to Business Insider.
Surely some cultures had noticed the unique shade surrounding the sun and the clouds.
But after looking at the Koran, the Hebrew Bible and ancient Icelandic and Chinese writings, Geiger found no such civilization to have distinguished the color blue.
This prompted Gieger to find out when and where the word "blue" first surfaced.
It turns out blue is the last color to appear in every language after red, yellow and green, all of which can be seen in nature.
But there are hardly any naturally blue foods, animals or plants.
Blue things tend to be artificial, and one such object inspired the creation of the word.
The ancient Egyptians were the first civilization to use a word for the color because they were also the first to make blue dye.
So before the Egyptians, did people see blue when they looked at the sky?
Researcher Jules Davidoff tried to answer this question with an experiment involving an African tribe that still has no word for blue.
He showed the Himba tribe a circle with 11 green squares and one blue one and then asked them to pick out the different square.
They either couldn't do it or took a very long time to identify the difference.
The Himba were easily able to spot a green square just faintly different from the others in the photo below, however, which makes sense considering they have so many words for green.
Here's the different square:
Davidoff concluded that without a word for a color, people might not even know they are looking at it.
The sky is only blue because the Egyptians gave us something to compare it to and made it part of daily life.