A camera obscura is a darkened room into which light enters through a small opening, projecting a live picture onto a screen. In a modern version, the view outside is reflected by a mirror through a lens, which projects it onto a viewing table. Looking down at the table one sees a living, two-dimensional image of the outside scene. The vibrant image promotes a feeling of serene detachment, reveals details otherwise overlooked, and enhances one's appreciation of the scenic beauty.

Although images formed by pinholes were known to the ancients, the discovery of lenses in the 15th century made it possible to obtain a bright and clear picture. The camera obscura reached its height of popularity in the 18th and 19th centuries, both as an amusement and as a drawing aid for artists. Vermeer, Canaletto, and Joshua Reynolds are known to have used one. During the 19th century there were hundreds in existence, but with the invention of photography in 1839 camera obscuras slowly disappeared. Today there are approximately seventy in the world.