The one that can be seen in a medium telescope from Earth is called the Cassini division. On a good night, you can even see the smaller inner division. Interestingly, Saturn is the only planet in the solar system whose specific gravity is less than water. This means that if you placed any of the other planets in a huge tub of water, they would sink. Titan is Saturn's largest satellite and is the second largest satellite in the solar system.
Titan is nearly half the size of the Earth.
It is also one of the easiest satellites to see. Iapetus orbits at nearly 4 million kilometers from Saturn. One side of Iapetus is heavily cratered while the other side appears to be almost smooth. This phenomenon still puzzles scientists. Dione is heavily cratered and also has winding valleys that are geological faults or cracks in the icy crust.