The color with the greatest wavelength in the visible spectrum is red.

Here's why:

* Wavelength and Color: The color we perceive is determined by the wavelength of light. Longer wavelengths correspond to redder colors, while shorter wavelengths correspond to bluer colors.

* Visible Spectrum: The visible spectrum is the portion of the electromagnetic spectrum that our eyes can detect. It ranges from violet (shortest wavelength) to red (longest wavelength).

Let me know if you'd like to know more about the electromagnetic spectrum!