Humanity has long projected its own patterns and shapes onto the landscape of Mars. From the famous "Face on Mars" photograph of 1976 — subsequently revealed to be an unremarkable mesa by higher-resolution imaging — to the many rocks and formations that Internet users have argued resemble terrestrial animals, the history of Mars observation is littered with examples of pareidolia: the cognitive tendency to perceive meaningful shapes in random forms.
Scientists are therefore cautious when a newly identified Martian feature is described, even informally, as resembling a pyramid. Yet the formation identified in images recently released from a high-resolution orbital survey is genuinely unusual — and the planetary geologists who have been studying it say it merits serious investigation.
The Structure
The feature is located in a sparsely mapped highland region in Mars's southern hemisphere, at a latitude roughly equivalent to northern Scotland if it were on Earth. It measures approximately 800 metres along its base — roughly the footprint of a small British market town — and rises to a peak some 300 metres above the surrounding plain. It has four roughly symmetrical faces that converge at a single point at the top.
What distinguishes it from the many wind-eroded buttes and mesas that dot the Martian landscape is the unusual regularity of its faces. Most natural rock formations show asymmetry and surface irregularities consistent with differential erosion by wind and ancient water flows. This structure's four faces appear relatively smooth and of approximately equal slope angle — a combination that, in the geological literature, tends to suggest either a particular type of volcanic intrusion or, more intriguingly, some form of impact-driven uplift.
"When we first saw this feature, our immediate instinct was to check the data quality. Formations this geometrically regular are unusual anywhere in the solar system. Mars has surprised us before, and it's doing so again."
Natural Explanations
Planetary geologists have already put forward several natural hypotheses. The most widely discussed is that the structure is a "yardang" — a type of rock formation sculpted by wind erosion — of unusual symmetry, created by the convergence of prevailing wind patterns from two or more directions over an extended period. Mars's thin but persistent atmosphere is known to produce powerful dust storms capable of sculpting rock over geological timescales.
A second possibility is that the feature represents a volcanic plug: the hardened remnant of magma that once filled a vent in a now-eroded volcano. As the softer surrounding rock weathered away, the more resistant core was left standing. On Earth, such features can produce strikingly geometric forms — the famous Devils Tower in the United States being a well-known example.
A third, more speculative hypothesis concerns the ancient impact record of the southern Martian highlands. Large asteroid impacts can produce complex patterns of uplift and fracturing in surrounding rock. In rare cases, this process is theoretically capable of producing symmetrical hill-like forms, though none matching this feature's apparent regularity has previously been documented on Mars.
What Happens Next?
The research team has submitted a proposal to direct one of the spacecraft currently orbiting Mars to conduct a more detailed imaging pass of the region. Higher-resolution stereo imagery would allow a precise three-dimensional model of the feature to be constructed, which should help discriminate between the competing hypotheses.
In the longer term, the location has been flagged as a potential point of scientific interest for future surface missions. Given the enormous logistical and financial demands of Mars exploration, it is unlikely to become a priority target in the near future. Nevertheless, the discovery is a reminder that the Martian surface, though studied for decades by orbiters and rovers, still holds surprises — and that the most interesting questions about Mars are often answered not by looking for life, but simply by looking more carefully at the extraordinary world that's already there.
