The moment the Earth appeared to 'breathe' has been caught on camera - and has sent social media's collective head spinning.
The video shows the ground rising and falling in a forest in Nova Scotia, Canada, reports the Mirror.
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It was uploaded to Facebook on 1 November by Brian Nuttell, who thought he knew why it was happening.
According to RT.com, he wrote: "The larger trees are doomed to blow down but are currently spared, the smaller trees around them help hold each other up, as the wind pushes the trees into one another. The punishing prevailing winds have taken their toll on the side hill, the roots have loosened and the mossy ground from the once shaded forest floor are giving way, soon to be toppled over."
A host of users commented on the video, with one writing: "That's pretty freaky. I have never seen that before."
Another said: "Why is it doing that?? Is it because the wind was moving the trees, and roots?? I wouldn't want to stand there,for fear the ground would open up, and swallow me!!"
One man had a theory behind it, writing: "The dead tree's died awhile back and their roots causing space underground,the ground on surface with the moss is very soft,the roots from the good trees standing are spread across the surface of the ground so when the wind blows..the ground moves with the roots...this is just my theory."
Another echoed: "I think what we're seeing here is the roots of the trees lifting the ground do to high winds."
Some just called it "creep and scary" and "cool", while one woman wrote: "Mother Earth breathing heavy."
What do you think is happening?