They glow blue when they’re ripe. Ever looked at a banana under a black light? Neither had scientists until 2008, when they discovered that the fruit fluoresces bright indigo at the peak of its ripeness. The glowing is the result of a chemical that’s created as the green chlorophyll in the peel breaks down. Researchers think this might help banana-eating animals that can see UV light, such as insects and bats, to know when it’s time to chow down.

They won’t get you high, but they might make you healthier. Sorry, hippies—the highs promised during the 1960s “mellow yellow” peel-smoking craze turned out to be all in users’ heads. But banana peels, especially green ones, could be a source of dopamine and other antioxidants for producing nutraceuticals. One study even found that banana peel extract could help treat enlarged prostates.