Visible light is the only kind of electromagnetic waves that are visible, however there are 7 types of electromagnetic waves, or we can call them electromagnetic radiations. Rank based on wavelength, from high to low, they are:

Radio wave

Microwave

Infrared Ray

Visible light

Ultraviolet Ray

X-ray

Gamma Ray

Notice that Gamma Ray has an extremely small wave length and can be as small as 1E-15 m.