NASA's Cassini spacecraft pinged the surface of Titan with microwaves, finding that some channels are deep, steep-sided canyons filled with liquid hydrocarbons. One such feature is Vid Flumina, the branching network of narrow lines in the upper-left quadrant of the image.
NASA / JPL-Caltech / ASI
The canyons of Vid Flumina are seen in this view from Cassini's radar mapper. More information.