Here's The Horrifying Sound An Aztec Death Whistle Makes
The Aztecs really knew how to scare the shit out of people, and that's certainly evident by the death whistles they created. These devices are believed to be used in battle, and when blown, imitate the sounds of humans in agony. Imagine making your way through a dense treeline and just hearing a dozen of these constantly going off all around you. It wouldn't be a pleasant experience! Check out what they sound like below at around the 2:24 mark: