The Poggendorff Illusion is a visual phenomenon that occurs when a diagonal line is interrupted by a vertical or horizontal edge. People perceive the two segments of the diagonal line as misaligned, even though they are actually straight and continuous. This illusion highlights how our brains interpret visual information based on context. First described by Julius Poggendorff in 1860, the illusion demonstrates the complexities of visual perception. It shows that our understanding of spatial relationships can be influenced by surrounding shapes and lines, leading to misinterpretations of alignment and position in our visual field.