A quadruple rainbow I saw in Ski, Norway, in July 2011. The fourth rainbow is a bit faint here.
The same photo with enhanced colors to make the fourth rainbow more visible.
Red channel image (all colors except red filtered out) of the original image. The fourth rainbow is more clear here.
Red channel image of the version with enhanced saturation. In real life, there was a hint of a fifth rainbow (quintuple!), which shows up a bit here too.
Click twice on each image for a larger version. Please contact me if you would like to reprint these images, or would like a larger version.
Note: I didn’t think there was anything special about a quadruple rainbow (I have seen them before) and also in taking photos of them, but here are some stories that seem to say something else:
Pictures: First Quadruple Rainbow Ever Caught on Camera – National Geographic