A rare green flash, also known as a green rim, illuminated the sunset at Cerro Pachón in Chile, captivating observers with its fleeting beauty. This optical phenomenon occurs when sunlight passes through the Earth's atmosphere, causing it to bend and split into different colors. As the sun approaches the horizon, shorter wavelengths such as green and blue are refracted more than longer wavelengths like red and orange. This differential refraction results in a brief green band appearing at the very top edge of the sun just before it disappears below the horizon.