The most unfortunately named planet of the Solar System
The seventh planet from the Sun, so far away it could be argued that the sun does not shine there.
It is a "giant planet," and arguably full of gases like methane and ammonia
, though its inner composition is various ices and rock. The result of this compositon makes the planet look like a nearly featureless blue ball. Coincidentally, this fit in with its namesake, the Greek god of the sky.
The planet, while visible to the naked eye (albeit very faint), is not one of the classic original planets, and is the first planet to be recognized as one via telescope, thanks to Sir William Herschel.
It has a ring system, like Saturn and other similar planets, a magnetosphere which draws objects into it, and of course moons
Its most striking feature, however, is that the gas giant is rotating on its side
, thanks to being smacked upside its head by two glancing blows
from planetoids about the size of Earth
early in its life. At the time of the Voyager 2 encounter, its south pole faced the Sun.
Currently, it's on its side in relation to the Sun. This has led to the realization (via observation from the Hubble Space Telescope) that the planet was actually two-toned, with a darker shade of blue on the north half of the planet.