Stereoscopy is a technique used to create the illusion of depth in images. It works by presenting two slightly different perspectives of the same scene, one for each eye. This mimics how human vision perceives depth, allowing viewers to experience a three-dimensional effect from a two-dimensional image. The most common method of stereoscopy involves using special glasses, such as anaglyph glasses with red and blue lenses, or polarized glasses that filter light differently for each eye. Stereoscopic images can be found in various media, including 3D movies, virtual reality, and stereoscopic photography.