Mysterious formations on Mars have fueled extraordinary claims that an ancient city was built beside a long-lost shoreline. The wild theory centers on the Cydonia region, where unusual hills and mesas have been compared to a human face, a pyramid and the remains of buildings. Supporters claim NASA's Mars orbiter has captured a distinct boundary between rugged highlands and a smooth basin where an ancient body of water may once have stood. Several of the region’s best-known formations, including the so-called Face, D&M pyramid and City, appear to be clustered along that boundary. UFO researcher Jason Martell, a regular guest on the History Channel's show Ancient Aliens, argued that their arrangement resembled the waterfront cities built throughout human history. Martell suggested that the Face may even have been positioned as a monument overlooking the water and nearby settlement. But the argument is based largely on visual interpretations of the landscape rather than geological analysis or physical evidence. There is no proof that the formations were constructed, that the proposed boundary was genuinely a shoreline or that an intelligent civilization ever inhabited Mars. The claim began with an apparent change in the terrain visible in orbital imagery of Cydonia.

On one side of the proposed dividing line, the ground appeared elevated, rugged and filled with prominent formations. On the other was a flatter, smoother expanse that the writer suggested could once have been covered by water. A hand-drawn line was then added to the image to illustrate where the supposed ancient shoreline may have run. The writer argued that the unusual formations appeared to follow this boundary in a pattern that was too striking to be accidental. If they were artificially constructed, their location beside a possible basin would mirror the way civilizations on Earth developed around water, according to the claim.

Waterfront settlements gained access to food, transportation, trade and other resources that allowed them to grow. In a blog post, Martell compared the proposed Cydonia settlement with cities including Venice, Alexandria, Amsterdam, Singapore, Dubai and Manhattan. Ancient settlements such as Memphis on the Nile and Ur beside the Euphrates were also offered as examples of humanity’s tendency to build near water. The theory further claimed that major monuments are frequently positioned where they can be seen from surrounding settlements or waterways. From that perspective, the Face may have overlooked both the proposed basin and the elevated formations identified as a city.

However, that comparison depends on first assuming the Martian formations were monuments and buildings, the very assertion the theory is supposed to demonstrate. The smooth basin does not, by itself, establish that an ocean or lake existed there, while a visible change in terrain can result from numerous natural geological processes. The proposed shoreline was also traced by hand, meaning its position depends heavily on the observer’s interpretation of the image. No measurements, sediment analysis or geological examination were presented to confirm that the boundary was shaped by water. Likewise, the apparent alignment of several formations does not demonstrate that they were intentionally positioned.

Humans naturally recognize familiar shapes and organized patterns in random landscapes, a phenomenon known as pareidolia. The Face, pyramid and supposed buildings may therefore be natural landforms that appear artificial when photographed under particular lighting conditions or viewed from certain angles. The writer acknowledged not being a geologist and said specialists would need to determine whether the differences in the surface were actually caused by water. Despite that admission, they described the visual evidence as compelling and suggested Cydonia could have represented the Martian equivalent of waterfront property. For now, the idea remains an imaginative interpretation of orbital images, not evidence of a lost city, constructed monuments or an ancient civilization on Mars.