A visual phenomenon refers to an occurrence that can be observed through sight, often involving unusual or striking visual effects. These phenomena can include natural events like rainbows and auroras, as well as optical illusions that trick the brain into seeing something that isn't there or perceiving an image differently than it actually is. Many visual phenomena arise from the interaction of light with various materials or atmospheric conditions. For example, mirages occur when layers of hot air bend light, creating the illusion of water on the ground. Understanding these phenomena helps us appreciate the complexities of vision and perception.