The Voyager 1 and 2 spacecraft flew by Saturn in 1980 & 1981 and were able to pay only fleeting attention to Titan, the second largest moon in the solar system and the only moon with an appreciable atmosphere.
Cassini And Titan: Saturn's Moon Shows Its Secrets [Infographic]
The clouds that make Titan featureless in visible light have now been pierced several times in infrared light by the robot Cassini spacecraft currently orbiting Saturn. These images have been compiled into the above time-lapse movie.
Here are three of the greatest discoveries of the Cassini-Huygens mission, which was 10 years old in 2014. The discovery of geysers on the moon Enceladus, lakes of liquid methane on Titan, and the a picture taken from the surface of Titan by the Huygens lander. Mona Evans, "Titan - Planet-sized Moon of Saturn" http://www.bellaonline.com/articles/art182860.asp