Tucked away on Mount Hachimantai in northeastern Japan is a lake called Kagami Numa. Most of the time it’s pretty ordinary looking, but if you go there at the right time you might be lucky to get a glimpse of a phenomenon which transforms the lake into what looks like a giant eye. Local legend has it that it’s caused by some lovelorn dragons in the area. BBC World of Wonder

Video taken by Hiromi Tanoue