After 20 years, a British scientist found a woman who can see 99 million more colors than the average human.

Most people can see one million colors, Discover Magazine reports. But neuroscientist Gabriele Jordan found a female doctor in England who has supervision.

The magazine explains how normal people see color:

An average human, utterly unremarkable in every way, can perceive a million different colors. Our powers of color vision derive from cells in our eyes called cones, three types in all, each triggered by different wavelengths of light. Every moment our eyes are open, those three flavors of cone fire off messages to the brain. The brain then combines the signals to produce the sensation we call color.

But some people have four cones, which scientists suspected could mean they have the ability to see more colors.

Jordan and her team constructed a test where three circles flashed on a screen. To a normal person, they'd all appear the same. Only a person with supervision would be able to distinguish between the three:

Jordan gave the test to 25 women who all had a fourth cone. One woman, code named cDa29, got every single question correct. “I was jumping up and down,” Jordan says.

Jordan told the magazine that it's impossible to know or describe what the world looks like to the woman who can see 100 million colors.