Saturn's moon, Titan

Titan is a unique world with a thick atmosphere and huge seas of liquid hydrocarbons. Titan is the second largest moon in the solar system, only being slightly smaller than Jupiter's moon Ganymede. This planet-like moon is much larger than our moon and even larger than the planet Mercury, though it is less massive. Titan is the only moon in the solar system with a thick atmosphere, and the only other world in the Solar system, besides Earth, with bodies of liquid on its surface.