Your daily adult tube feed all in one place!
From a howling wolf to a bloodcurdling scream, there are some sounds that send a chill down the spine of even the bravest horror movie aficionado.
But these chilling noises pale in comparison to one sound, which has been described as the 'scariest in the world'.
The Aztec Death Whistle is somewhere between a spooky gust of whistling wind and 'the scream of a thousand corpses', according to experts.
It was used by the Aztecs during sacrificial ceremonies, and was said to honour the god of wind, Ehecatl.
So, are you brave enough to listen to it?
The Aztec Death Whistle is somewhere between a spooky gust of whistling wind and 'the scream of a thousand corpses', according to experts
Brave experts recently recreated the noise of the Aztec Death Whistle, by building a new version of the legendary instrument with a 3D printer.
They created their new whistles based on the design of the skull-shaped original, which was found with a skeleton in Mexico in the late 1990s.
A video of the 3D-printed whistle was posted by the Action Lab, an educational YouTube channel dedicated to performing scientific experiments.
'This has been deemed the most terrifying sound in the world,' says presenter James J. Orgill.
'Believe it or not, this is not a human scream.
'The sound that the death whistle makes innately strikes fear into your heart.'
It was back in 1999 that the original Aztec Death Whistle was found held in the hand of a headless skeleton during the excavation of an Aztec temple in Mexico City.
'Archaeologists first thought that this must be some sort of toy and they didn't think much about it,' says Orgill in the video.
'It wasn't until 15 years later for some reason a scientist blew into the hole in the top of it and this is the sound that came out.
'It was a startling discovery because it sounded like a screaming human.'
Although the exact purpose of the death whistle has been lost to history, there are several leading theories.
In 1999, the original Aztec Death Whistle was found held in the hand of a skeleton during the excavation of an Aztec temple in Mexico City
Some experts think the Aztecs likely used the noise to help people's souls travel to the afterlife when they were sacrificed.
Perhaps the original skeleton was buried with the device as a protection, to scare away evil spirits as they left this world.
But the whistles may also have been used by warriors to 'strike fear in the hearts of the enemies' at the beginning of battle, Orgill claims.
The shape of the whistle mimics the shape of a human larynx, according to the expert.
Once the user blows into it, the air is split into two, creating oscillating sound waves that circulate around a large chamber before escaping from a second hole.
Some of the whistles have a ball inside the chamber, often made of cork, which bounces around and further distorts the sound.
During the video, Orgill tests out modern-day versions of the Aztec Death Whistle made using a 3D printer from US firm HeyGears.
They produce different sounds depending on how big the object is and where exactly they're placed on the lips when blown into.
People can already buy their own death whistles on Amazon made from a variety of materials such as resin, ceramic and even carbon fibre.
According to one Amazon product description, they 'emit a scream that sounds like a woman being in horrible agony' and are 'perfect for Halloween'.
They also make a helpful prop for dramatic productions – for example, for scenes when characters hear a scream off-stage.
'For some reason the effect of making it sound like a scream is stronger when you don't actually watch the person blowing into the whistle,' Orgill says.
'[This is] probably because your brain knows it's a whistle.'
The Aztec Death Whistle attracted the attention of archaeologists because of their skull shape, but it is only recently that their fearsome noise has been investigated.
Mexican musician Quijas Yxayotl thinks the death whistle was used for special ceremonies, including the Day of the Dead, and in warfare.
'They played over a hundred instruments; a hundred death whistles marching to cause a big psychological effect to the enemy,' he said.