The color red does not really exist. It is an illusion.
Yes, there really is light with a wavelength of 660 nanometers but this light is not really red. It is just a wave. Your brain interprets it as red.
In fact, most other mammals cannot see red because they lack the receptors for it. To them the concept of red simply does not exist.
The old saying about a tree falling in the woods is true. A falling tree will always emit the vibrating energy that we call sound waves, but with nobody around to hear it this energy would not be sound because sound only exists in your brain.
The same is true for all of our senses.
Researchers have located the exact gene, called TAS2R38, that allows us to taste bitterness. People who don’t have this gene are unable to perceive that this flavor exists.
How many tastes are there that we can’t taste and sounds that we can’t hear and odors that we can’t smell? People with synesthesia may have senses that you don’t have.