You've probably never wondered about the sound made by 140 million monarch butterflies taking flight at the same time.
But this video will change all that.
Because not only are the images of the orange, black and white insects simply incredible, but they're audibly stunning too.
YouTuber and tropical entomologist Phil Torres, patiently waited at Mexico's Sierra Chincua Reserve to capture the exact moment millions of migrating butterflies take off after winter.
"It's one of the rarest sounds on Earth," said Torres.
"The sound of millions of monarch butterflies flying around is a world treasure and we need to protect this incredible species."
They sound so peaceful and just like a waterfall!