As a child I was always entranced by geography books - not the words, so much, but more the detailed places of volcanic lava fields, complex river deltas, and amazing mountainous terrains.
Looking at the new iOS app, Earth Primer, I can feel that same sense of scale and awe absolutely rekindled.
Earth Primer is, in the words of the developers, a 'science book for playful people', and while it looks like it would be a great educational tool for kids, I can think of more than a few adults who could lose hours to the interactive maps and geographical tools. You can see one in action on the app's website, where you can erode away a mountain range so it's rain-shadow disappears and moisture can reach the desert beyond.
The interactive displays bring alive volcanos, the water-cycle, how biomes workm, and much more.
Even better, you can unlock 'sandbox mode' which lets you create new landscapes and then unleash natural forces to shape them. At the risk of going full-nerd, here, I'm going to suggest that this would be excellent for creating maps and worlds of fantasy games and novels.
It's $US9.99, and out now.