The majority of humans are trichomats i.e. we have three different types of cells in our eyes, each sensitive to a different colour. I already knew about colour blind humans, i.e. dicrhomats. About 1/20 of males are colour blind.

Now I found out that some humans, apparently, are tetrachromats. Find out if you are one here (may not work on all computer monitors?)

Many animals are normally tetrachromats, for example birds. Then there are crazy examples like the mantis shrimps which seem to have cells sensitive to 16 different light wavelengths!

I wanted to end this with a video of interesting mantis shrimp courtship, as extremes in nature, like the peacocks' tail, are often due to sexual selection, and lead to fascinating displays, even if you are not a female of the species in question. Unfortunately I could not find something fitting, so you will have to use your imagination!