♅Uranus

Uranus is an ice giant made mostly of water, ammonia, and methane ices, and the methane in its atmosphere absorbs red light to give it a cyan hue. Its most peculiar feature is that its axis is tilted about 98°, so it circles the Sun almost lying on its side, rolling like a ball. As a result, its polar regions have 42 years of continuous day followed by 42 years of night. It also has the coldest atmosphere in the Solar System (as low as about -224°C). Discovered by telescope by William Herschel in 1781, it became "the first planet discovered by humankind," unlike the other planets known since antiquity.