Final answer:
On the horizon line, the vanishing point is always found, which is key in the technique of linear perspective used in art to create an illusion of depth.
Step-by-step explanation:
On the horizon line, what you always find is a vanishing point. Linear perspective, a technique used in various forms of visual art to create the illusion of depth, relies on the optical illusion that parallel lines seem to converge as they recede into the distance. This is due to the fact that as these parallel lines, known as orthogonals, move away from the viewer, they appear to get closer together until they meet at the vanishing point on the horizon line. The vanishing point is central to achieving the sense of three-dimensional space on a two-dimensional surface, such as in the works of Perugino or in the photograph No: Life as a Picture-A Picture as Life by Wolf Vostell.