New radar images of Titan show surprisingly familiar terrain on Saturn's largest moon. The radar images show a strip 4,500 km (2,796 miles) long, straight through the Xanadu region. Some images show hills, valleys and dark sand dunes cut by river networks - the similarity to Earth is striking. Of course, Titan is so cold it can't be water; these rivers are probably formed by liquid methane or ethane. Cassini will return to Titan on Saturday, July 22 and capture images of the northern latitudes.