MERCURY
Taken about 40 minutes before Mariner 10 made its close approach to Mercury on September 21, this picture shows a large (230 kilometers, 142 miles) double-ringed basin (center of picture) located in the planet's south polar region. This picture was taken from about 55,000 kilometers. Click here for more.
This mosaic shows the planet Mercury as seen by Mariner 10 as it sped away from the planet on March 29, 1974. The mosaic was made from over 140 individual TV frames taken about two hours after the encounter, at a range of 37,300 miles (click to enlarge). Click here for more.