Unusual geological formations in the Cydonia region of Mars have prompted speculation about the existence of an ancient city beside a long-vanished body of water. These claims center on formations such as hills and mesas that have been compared to a human face, a pyramid, and the remnants of buildings.
Supporters of this theory point to images captured by NASA's Mars orbiter, which they interpret as showing a distinct boundary between rugged highlands and a smooth basin. They suggest this boundary could represent an ancient shoreline, with prominent formations like the "Face," the "D&M pyramid," and "City" appearing to be clustered along this line. UFO researcher Jason Martell has compared the arrangement to waterfront cities built throughout human history, suggesting the "Face" might have served as a monument overlooking a nearby settlement.
The theory's basis lies in the perceived change in terrain visible in orbital imagery. On one side of the proposed dividing line, the ground is depicted as elevated and rugged, featuring prominent formations. On the other, a flatter, smoother expanse is interpreted as a former basin that may have once been covered by water. A hand-drawn line has been used to illustrate the supposed ancient shoreline, with the argument that the unusual formations follow this boundary in a pattern too striking to be accidental.
If these formations were artificially constructed, their location beside a possible basin would mirror how civilizations on Earth developed around water sources, providing access to food, transportation, and trade. Martell has drawn parallels between the proposed Cydonia settlement and historical cities such as Venice, Alexandria, and Manhattan, as well as ancient settlements like Memphis and Ur.
The theory further posits that major monuments are often positioned to be visible from surrounding settlements or waterways. From this perspective, the "Face" formation could have overlooked both the proposed basin and the elevated formations identified as a city. However, this interpretation relies on the initial assumption that the Martian formations are artificial monuments and buildings, which is precisely what the theory aims to demonstrate.
Critics note that the smooth basin does not, by itself, confirm the existence of an ancient ocean or lake, and that visible terrain changes can result from numerous natural geological processes. The proposed shoreline's position is also heavily reliant on subjective interpretation, as it was traced by hand. No geological analysis or measurements have been presented to confirm that the boundary was shaped by water.
Similarly, the apparent alignment of formations does not prove intentional positioning. The human tendency to recognize familiar shapes and organized patterns in random landscapes, a phenomenon known as pareidolia, may explain why the "Face," pyramid, and supposed buildings appear artificial. These could simply be natural landforms that resemble artificial structures when photographed under specific lighting conditions or viewed from certain angles.
While the visual evidence is described by proponents as compelling, the idea of an ancient Martian city remains an imaginative interpretation of orbital images. Without geological evidence or proof of artificial construction, it does not constitute evidence of a lost city or an ancient civilization on Mars.