Stonehenge at Night, picture taken by electrical engineer and photographer Harold Edgerton.

Illuminated by a 50,000 watt-second flash in the bay of a night-flying airplane 1500 feet above the ancient monoliths, Edgerton’s pictures of Stonehenge served as a demonstration to the Allied commanders of the potential for nighttime reconaissance photography. Edgerton was on the ground with a folding pocket camera braced on a fence post as the plane flew overhead. Simultaneously, the monument was recorded in perfect detail by a camera in the plane. The target was chosen because it was remote enough to allow the equipment to be tested without arousing unwanted interest.