Astro-image of the day: planet-spanning wall on Iapetus

Okay, I'm using "planet" just for dramatic effect, because Iapetus is a moon of Saturn. But wow! The story linked via the image argues that this 12-mile-high, 60-trillion-mile-long (or something) wall could only have been built by intelligent beings using, oh, say, nanofacturing methods.

Look at this amazing shot:

Click the image to see the story.

The author then examines close-ups like this one, "clearly showing" square-walled architecture:

Click the image to see the story.

Inspiring stuff for SF writers! Wacky, too, but hey - it's SF! We can use material like this for cool settings. Unfortunately, NASA debunks the argument that Iapetus is a manufactured world. (But of course they would! The Man is in league with the aliens!)

Thanks to james_nicoll for the tip!

Best,
Chris