The human eye can see millions of colors — but no eyes have ever before beheld "Olo." Only five people on the planet — all from a team of researchers in California — have witnessed this brand new color.

Researchers behind a recent study claim to have discovered a new color that the natural, naked eye cannot perceive — 'olo,' a hyper-saturated blue-green that occurs when a single kind of cone cell is stimulated in the retina.

Using an experimental technique called "Oz," researchers stimulated the human retina such that people saw a brand-new color.