Earth: The Blue Marble
The Blue Marble was a notable 20th century photograph taken of Earth from high orbit.
An image depicting this photograph was scanned by the Talosians as they reviewed the library computer files on board USS Enterprise in 2254. (TOS-R: "The Cage")
This photograph, officially designated "AS17-148-22727", was originally taken from Apollo 17 on December 7, 1972, during the last manned mission to the moon. [1]