In the 1800s, the Rocky Mountain locust brought massive destruction to Western settlers. Then, the insects suddenly disappeared-almost without a trace. Now scientists hope to find a reason for the locust?s extinction. What caused the Rocky Mountain locust to disappear? Where will the scientists find the answers? Welcome the sights and sounds of the world with the Footprint Reading Library. Accompanied by original video material developed by National Geographic Digital Media, this is the first non-fiction reading series to present fascinating real-world stories in three formats: print, audio, and video.
