Summary: A vanished glacial lake, huge ice dams breaking up (think Ice Age II, only better), a tortured landscape, and the brave and clever geologists (both male and female, although predominately male) who figure out the clues and solve the Mystery of the Megaflood! This is almost a prefect non-fiction video. There is a lot of dramatic action, but it's geological and doesn't involve people getting hurt. The mystery that the geologists are trying to solve gives a plot-like structure to it, which helps hold the viewer's interest. The images are stupendous:
It's hard to put a bottom line on the age of viewers who would like this; for what it's worth, my six year old loves it. I think it should appeal to any kid who likes rocks!
Note on Gender Issues: I liked it because it showed a brave female geologist rappelling down a cliff. I fret a bit about the predominance of men in non-fiction videos, especially in their role of narrators (leading to the impression that men = the ones who have knowledge, which is not what I want my boys to believe). It is very rare to find a really good sciency video narrated by a woman. The DK folks found a female narrator for their videos about mythological creatures, for instance, but all the science ones are male. So if anyone knows any hard core science videos with female narrators, let me know!
If you'd like to learn more about the geological details, here's the link to PBS.