On 8 March 2004, NASA’s Mars Exploration Rover Spirit took the first image of Earth from Mars, an hour before sunrise.
According to the image’s description, the photo is a mosaic of images taken by the rover's navigation camera showing a broad view of the sky, and a panoramic image of Earth. The contrast in the panoramic image was increased twice to make Earth easier to see.
[via Twisted Sifter, images from NASA/JPL/Cornell/Texas A&M]