Several strange signs called ?crop circles? have been discovered in the fields of southern England. These mysterious circles are puzzling to everyone, even scientists. There are several theories about who -or what- made them. Could it be humans who did it? Or could it be something else ... 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.
