Neptune’s supersonic winds and icy storms revealed a planet so extreme that it forever changed our picture of the solar system. The discovery of Neptune in 1846 was not just the triumph of mathematics ...

Why it's so special: Only one spacecraft has ever visited the eighth and most distant planet from the sun. On Aug. 25, 1989, NASA's Voyager 2 spacecraft took the first-ever close-up images of Neptune.

When you buy through links on our articles, Future and its syndication partners may earn a commission. What it is: One of the final photographs of Neptune taken by NASA's Voyager 2 probe Where it is: ...