We can see electromagnetic radiation with wavelengths in the range of
400 nm to 700 nm.
The electromagnetic spectrum covers an enormous range of wavelengths.
The wavelengths of gamma rays are about 10⁻¹⁴ m.
The wavelengths of radio waves can be 10¹⁰ m.
The part of the spectrum that we can see (the visible spectrum) is only the tiny region between 400 nm and 750 nm.