Conspiracy theorists have been on the hunt to prove NASA has been lying to the public about life on Mars. Now, one may have revealed some evidence which seemingly shows an ancient structure on the Red Planet. The image, taken by NASA satellites hovering over Mars, appears to depict ancient structures and even stone carvings.

In the picture, which includes annotations, walls look as if they appear to have been built as if they are part of a fortress,

Prominent alien hunter Scott C Waring says this is “100 percent” proof that life does, or did, exist on the Red Planet.

He wrote on his blog, UFO Sightings Daily: “I found a lot of ancient structures in a Mars photo today. These structures are long and almost resemble walls, but are buildings in long lines.

“I also discovered a face carved into a hill top, but is so ancient, it may be hard for some to see its details.

“This is 100 percent proof that ancient civilisations once flourished on the surface of Mars, and that NASA doesn't want you to know about it.”

Sceptics and NASA would say the ‘city’ and other similar findings are just the effects of pareidolia – a psychological phenomenon when the brain tricks the eyes into seeing familiar objects or shapes in patterns or textures such as a rock surface.

This is not the first time that ‘evidence’ of aliens on Mars has been discovered.

Earlier this year, an "alien face" was found in a NASA satellite image of Mars, according to more bonkers claims.

Mr Waring was convinced it could be a rock carving, done by a Martian race, in the same way ancient Britons carved out the chalk figures in hillsides like the giant of Cerene Abbas in Dorset and the Long Man of Wilmington in East Sussex.

However, NASA insisted the rock is just a meteorite impact crater that has been left in the unusual form by later erosion.

When NASA released the image under the "alien head" caption, it said: "The image shows an impact crater in Chryse Planitia, not too far from the Viking 1 lander site, that to seems to resemble a bug-eyed head.

"The two odd depressions at the north end of the crater (the ‘eyes’) may have formed by wind or water erosion.

"This region has been modified by both processes, with water action occurring in the distant past via floods that poured across western Chryse Planitia from Maja Valles, and wind action common occurrence in more recent history.”