Why Saturn is said to be unique characteristic?

Answer 1

NASA overview of Saturn stated, "Adorned with thousands of beautiful ringlets, Saturn is unique among the planets. It is not the only planet to have rings – made of chunks of ice and rock – but none are as spectacular or as complicated as Saturn's." This therefore indicates the planet to be unique. Also Saturn's other reason that it is unique is that it’s the only planet whose density is less than water.

Answer 2

Saturn is not unique. While Saturn's ring system is larger, more extensive and more well defined, both Jupiter and Uranus have rings, and it seems likely that other large planets are likely to have rings as well.

Saturn's other "claim to fame" is that it is the only planet - in THIS solar system - whose overall density is less than water. Again, this is somewhat unusual, but probably isn't unique.

Answer 3

The only moon known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found.

Answer 4

It's rings.