The καμερά obscura, or "dark chamber," is an optical device that projects an image of its surroundings onto a surface. It consists of a darkened room or box with a small hole (aperture) on one side. Light passes through this hole, creating an inverted image of the outside scene on the opposite wall or surface. This phenomenon occurs due to the way light travels in straight lines. The καμερά obscura has been used for centuries in art and science, helping artists understand perspective and aiding in the study of optics. It is considered a precursor to modern photography.