Yes, there are mediums in which light cannot propagate or travel. These mediums are typically referred to as opaque. When light encounters such a medium, it is absorbed, reflected, or scattered, preventing it from transmitting through.
Opaque mediums can vary depending on the specific wavelength or frequency of light being considered. For example, certain materials may be opaque to visible light but transparent to other forms of electromagnetic radiation such as radio waves or X-rays. The opacity of a material depends on its interaction with the photons of light and the structure of the material at the atomic and molecular levels.
It's worth noting that even transparent materials can become opaque if they are thick enough or contain impurities or defects that scatter or absorb light. Additionally, in extreme conditions such as very high densities or temperatures, even typically transparent materials can become opaque due to interactions between particles or the alteration of their electronic structure.
In summary, while light can propagate through most transparent mediums, there are indeed materials and conditions where light cannot travel, rendering those mediums opaque.