The Transmission Electron Microscope (TEM) is a powerful imaging tool that uses a focused beam of high-energy electrons transmitted through an ultra-thin specimen to produce detailed, high-resolution images at the atomic scale. Unlike light microscopes, TEMs exploit the short wavelength of electrons to achieve magnifications exceeding 1 million times, revealing internal structures, crystal lattices, and chemical compositions with nanometer precision. Operating in a vacuum, TEMs are essential in fields like materials science, nanotechnology, and biology, enabling researchers to visualize and analyse the fine architecture of cells, nanoparticles, and complex interfaces.