What does a wondrous cloud of monarch butterflies taking flight at once sound like? A waterfall, of course.

YouTuber and tropical entomologist Phil Torres, who posts short documentary videos as The Jungle Diaries, patiently waited at Mexico's Sierra Chincua Reserve to show this exact moment, when 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."

It's not just audibly stunning, either. Torres' images of monarch butterflies clustered together on tree branches and trunks for the winter are quite simply incredible.