First used centuries ago, this unique form of whistle makes the haunting sound of a blood-curdling scream.
What's the most disturbing sound you can think of ? Chances are, it wouldn't be far from what can be produced with one of the world's most unique and disturbing whistles.
First discovered by archaeologists during the excavation of a temple in Mexico City in 1990, the Aztec death whistle (or at least an early version of it) was developed and then exclusively used by the Nahuatl-speaking people of the Mexica Empire sometime around 500-700 years ago.
Shaped like a skull, the whistle is capable of producing a loud shrieking sound that resembles a blood-curdling scream, although this is only true of much later, larger reproductions of the whistle as the original whistles made centuries ago were smaller and made a much softer sound.
Even so, modern versions of the whistle are very much the real deal and sound pretty terrifying.
The original purpose of the whistle was likely ceremonial in nature, but these days they can serve multiple uses (such as giving unsuspecting individuals a good scare!)
You can check out a few example whistles (and what they sound like) in the video below.