On December 24, 1968, the Apollo 8 crew photographed the iconic “Earthrise” photo above. This view of the Earth rising from the horizon of the moon is credited with helping humans realize the fragility of their home. A couple of years later, in 1970, the first Earth Day was celebrated. Another iconic photo “Blue Marble”, the first photograph in which Earth is in full view, was taken in December 7, 1972 by the Apollo 17 crew.
Other iconic images of the earth can be found here.