Because the cell structures are so small, to clearly view them, requires a microscope that has a higher power of magnification than light microscopes can prove. This is usually an Electron Microscope.
Electron microscopy (EM) is a technique used to obtain high-resolution images of biological and non-biological specimens. It is often used to investigate the detailed structure of tissues, cells, organelles, and macromolecular complexes. (UMass Chan Med School Website)
