These are the best optical illusions I’ve ever seen.
Light as we see it is the brain’s interpretation of a certain band of wavelengths on the electromagnetic spectrum, running from approximately 400-700 nm, as seen above. But can you find pink/magenta on that linear scale?
This is because the electromagnetic spectrum spreads far beyond what humans can see, including infrared (beyond 700nm) and ultraviolet (below 400nm). However, in our minds, this little linear slice that we can interpret is turned into a circle, creating the colour pink by blending the 400nm and 700nm ends of the visible spectrum. You might have seen this circle in art class as the colour wheel.
Pink has no wavelength to call its own - it exists only in our minds.