A mirage is an optical phenomenon that occurs when layers of air at different temperatures bend light rays. This bending creates the illusion of water or a reflective surface, often seen in deserts or on hot roads. The effect happens because warm air near the ground is less dense than the cooler air above it, causing light to refract. Mirages can be categorized into two types: inferior and superior. An inferior mirage appears below the horizon, making it look like water on the ground, while a superior mirage appears above the horizon, often seen in polar regions. Both types result from similar atmospheric conditions.