This photograph of the moon's Copernicus crater shocked the world upon its release in 1966.

The snapshot, from the unmanned Lunar Orbiter 2, pre-dates the first manned moon landing by years. In fact, the orbiters were taking pictures of the moon to help NASA choose landing sites for the Apollo program.

Taken from an oblique angle, the image convinced people that there was real structure to the moon.

NASA scientist Martin Swetnick deemed it a "picture of the century" in a December 1966 Time article.

Today Dennis Wingo, a leader of a project to recover Lunar Orbiter images, seems to agree: "Looking at this Copernicus image, you can imagine yourself standing on a mountain looking at this amazing vista. It has that kind of depth to it."

(Related: Hear a 1969 audio history of the space age, including the Apollo 11 moon landing.)