Venus
On it's way to Jupiter, the Galileo spacecraft
made a flyby of Venus for a gravitational assist. These photos were
taken at that time- shortly before the Magellan mission arrived at Venus
to begin it's extensive mapping mission. This does not show tremendous
detail, but the sphericity is plainly visible.
Source page: http://www.jpl.nasa.gov/galileo/sepo/cruise/venus/venus.html
