Fireflies and jellyfish glow, but humans? Believe it. The phenomenon is a natural byproduct of the metabolic process, and scientists have long been aware of the presence of bioluminescence in most living creatures. But it wasn’t until 2009, when a team of Japanese researchers developed a camera 1000 times more sensitive than the human eye, that human bioluminescence was captured on film. The light show apparently works on a 24-hour cycle — brightest in the late afternoon and on the cheeks, forehead and neck. Next time someone tells you “you’re glowing,” you can take it literally.
That's just one of 11 insane features that you probably haven't thought about in the human body. Bone up on all of them at mental_floss. Link
(Unrelated image credit: Flickr user Scorpions and Centaurs)