Saturn's moon Titan features vast swaths of "sand seas" covered with row after row of dunes from 300 to 500 feet high.

Saturn's moon Titan features vast swaths of "sand seas" covered with row after row of dunes from 300 to 500 feet high. Radar images of these seas, which stretch for hundreds of miles, bear a stunning likeness to ranks of dunes in Namibia and Saudi Arabia.