Loud noise in Leave the World Behind has been explained by film's director

Warning: Spoilers... obviously

Netflix has dropped yet another eerie movie depicting the end of civilisation as we know it.

Leave The World Behind has been dividing viewers since it finally landed on the platform last week.

Check out the trailer for yourself:

The movie, which is based on the book of the same name, follows a family of four who leave New York City to spend some time in a remote(ish) town.

However, the calming break takes a very sinister turn when a man and woman turn up at their door in the middle of the night.

And so begins a whole lot of creepy goings on.

For those of you who've not seen it yet, I would stop reading here and go and do so, but seeing as you're here, the synopsis reads: "A family vacation on Long Island is interrupted by two strangers bearing news of a blackout.

"As the threat grows, both families must decide how best to survive the potential crisis, all while grappling with their own place in this collapsing world."

Now, after getting off to a pretty frosty start, the two families start to witness some seriously weird stuff - planes crashing, creepy drones dropping sinister flyers, malfunctioning driverless cars, etc.

But one of the most troubling and generally horrible moments of the whole film is 'the noise'.

Netflix

While Amanda (Julia Roberts) is out in the woods, a deafening noise comes out of nowhere.

The following day, her son, Archie (Charlie Evans) starts to feel really unwell, with his teeth literally falling out of his head. Yikes.

At the time, the two incidents seem unconnected, however, when they look to the local prepper Danny (Kevin Bacon) for help, he suggests a possible source of the bizarre ailment.

Holding a gun to G.H. Scott (Mahershala Ali) and Clay (Ethan Hawke), Danny suggests it could be the result of something called Havana Syndrome, a phenomenon that saw ultrasound and microwave weapons used to attack US government officials.

One of the symptoms, he says, is a loss of teeth.

And it would appear that that certainly was an inspiration for the noise, according to the film's director, Sam Esmail.

Netflix

Speaking at the Netflix Tudum event, he said: “When I read that in the book, I immediately got excited and spoke to my sound designer who I’ve worked with since the first season of Mr. Robot, Kevin Buchholz.

“Before we shot a frame of the film, we were trying to dial in this sound. We took elements of Havana Syndrome, which is a mysterious sound that they still have not gotten to the bottom of that has been causing people to have ailments.”

To add authenticity to the film as well, Esmail also kept the noise a bit of a secret from the cast.

“I didn’t even tell them I was going to play it while we were shooting the scene,” he explained.

“I believe Julia was the first one to have heard it, so when we did her close-up and that moment came, we blasted the sound and that was her genuine reaction.”

Bet that was a nice surprise for her, wasn't it?

Leave The World Behind is available to watch on Netflix now.