Conspiracy theorists have long pointed to extra-terrestrial life existing millions of miles from Earth, but now some believe they've found conclusive evidence a little closer to home.
Images found in footage of Mars, taken from NASA's Mars Global Surveyor, appear to show a gigantic 2.1km long vessel which theorists are claiming is an "alien mothership".
UFO hunters firmly believe the discovery is evidence of an alien civilisation on the rocky planet.
"I have processed, colourised and rebuilt the object and in my opinion it is a craft of some kind, possibly tens of thousands of years old," the video's description reads.
It was posted to YouTube by an account called Paranormal Crucible, which has previously suggested ancient alien artifacts have been found in Mexican caves, as well as tree stumps and whale bones on Mars.
"It's also over a mile long, so this must have been a mothership, either a Martian one or possibly an off planet alien species, but why did it crash?"
The video goes as far as to label certain features of the alleged ship, pointing out possible locations of the cockpit and the ship's hull.
However, commentators have rubbished such claims, insisting it is only a piece of raised ground or a rock formation.