A camera obscura is a dark box with a small hole in the front.
Light passes through this hole and lands on the back of the box,
casting an upside-down version of the scene.
Although this idea had been understood by scholars for hundreds of
years, Leonardo da Vinci (1452-1519) was the first to write a detailed
description of the camera obscura in his Atlantic Codex in 1490.
An astronomer named Gemma Frisius (1508-1555) was the first to draw a
camera obscura around 1545.