For the curious
Titan is the only moon with a thick atmosphere, and the only place besides Earth known to have rivers, lakes and seas on its surface. Cassini's radar saw through the haze. Here is what it found, in plain words.
These are global elevation maps of Titan built from all the topography Cassini collected: radar altimetry, SARtopo and stereo images. Real measurements cover only about 9 percent of Titan, so the gaps are filled by interpolation. The files are map-projected ISIS3 cubes, so GIS software can place them on Titan without extra georeferencing. Start with the 4 MB global map if you want something small.
Titan has river channels. This shapefile traces the channels visible in Cassini radar images across the whole moon. Every segment records how certain the mapping is, its stream order, its apparent width and its length. It is small, so it is a good first download for a class project.
These mosaics stitch every Cassini radar swath into one picture of Titan's lower latitudes. The mosaic is split into four longitude quadrants only because the files are so large. Each quadrant is an ISIS3 cube of about 2.8 GB with its own DOI.