Conspiracy theorists believe they've found proof of a downed 'alien mothership' on the surface of Mars.
According to the YouTube channel Paranormal Crucible, the 1.3-mile long craft is evidence of an alien civilisation that crash-landed on the rocky planet.
The images from the video were found in footage taken from NASA's Mars Global Surveyor - which surveyed the red planet until 2006 when the space agency lost contact with it.
"I have processed, colorized and rebuilt the object and in my opinion it is a craft of some kind, possibly tens of thousands of years old," explains the description underneath the video.
Annotated image of the 'alien mothership'
Some commentators have poured cold water on the theory, insisting it is only a piece of raised ground or a rock formation.
But the UFO hunters behind the channel are convinced of its authenticity.
"The object is too degraded to enhance totally so I have rebuilt it using the points of interest that are shown in the video," the video states.
"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 has been on YouTube for a week and has amassed over 6,000 views.
However, this is far from the first time something strange has been spotted hiding in pictures of the Martian surface.
Strange domes and rock outlines resembling human-like items are often picked up on as evidence of pareidolia: when the brain is tricked into seeing familiar sights in strange objects.