Across the ages, humans have sculpted the Earth with intricate geoglyphs, from the enigmatic Nazca Lines in Peru to the monumental mounds of ancient civilizations. These creations, etched into landscapes, have long been interpreted as sacred symbols, territorial markers, or even messages to the heavens. The Nazca Lines, unseen for centuries until aviators soared over the arid Peruvian plateau in the 1930s, revealed a stunning array of geometric patterns and animal figures. Archaeologists suggest these were crafted for worship or to mark celestial alignments, while others speculate they were signals to divine beings or extraterrestrial observers.
This human impulse to leave enduring marks on the land finds a curious echo in a bold proposal from the 1820s by German mathematician Carl Friedrich Gauss. He envisioned a colossal geometric landform in the Siberian forest, depicting the Pythagorean Theorem with a mᴀssive right triangle and three squares. By planting wheat in the cleared areas to contrast with the dense pines, Gauss believed this design would be visible from the Moon or Mars, signaling intelligent life to alien watchers. Though his vision was never realized, it reflects a timeless human desire to communicate beyond our world.
But what if such a signal exists not on Earth, but on Mars? In 2014, a groundbreaking book, Archaeology, Anthropology, and Interstellar Communication, edited by astrobiologist Douglas A. Vakoch, explored this possibility. NASA and SETI scientists, alongside archaeologists and anthropologists, proposed that rock art or sculptural carvings on other planets could be evidence of extraterrestrial intelligence. The challenge, they noted, lies in distinguishing these from natural phenomena, as alien creations might mimic forms we attribute to nature. Could an ancient, lost civilization—on Earth, the Moon, or Mars—have left a message we’re not yet equipped to recognize?
The Martian Enigma: The Keyhole Formation
On January 11, 2011, NASA’s Mars Reconnaissance Orbiter (MRO) captured an image that sparked intrigue. In the Libya Montes region of Mars’ Syrtis Major hemisphere, the HiRISE camera revealed a peculiar formation: a wedge-shaped structure joined to a circular dome, resembling an exclamation mark or, more precisely, a keyhole. This image, labeled ESP_020794_1860, boasted a stunning resolution of 50 cm per pixel, showing the formation in crisp detail under the early afternoon Martian sun. The University of Arizona, which manages HiRISE, dubbed it an “exclamation mark,” but its keyhole-like shape captivated imaginations.
The discovery came to light in 2013 when Greg Orme, a researcher with the Society for Planetary SETI Research, shared it with The Cydonia Insтιтute. The image, posted on the Insтιтute’s discussion board under the тιтle Keyhole – Exclamation Mark on Mars, went viral. YouTube videos and online articles proliferated, often borrowing descriptions and drawings without credit. The keyhole became a sensation, fueling speculation about its origins.
Further investigation uncovered two earlier images of the same structure, both from 2007. The first, captured by the MRO’s Context Camera (CTX) in November (image P14_006672_1836_XN_03N267W), offered a resolution of 5 meters per pixel. The second, taken by the Mars Odyssey THEMIS camera in December (image V26406033), had a coarser resolution of 17 meters per pixel. Both images confirmed the keyhole’s distinct wedge-and-dome shape, with sunlight casting shadows that highlighted its sharp edges and ribbed dome texture. The consistency across these images, taken under different conditions, deepened the mystery.
A Message from Mars?
The keyhole’s precise geometry stands out against the flat, barren terrain of Libya Montes. Its sharp lines and structured form challenge the notion of a natural formation. Could this be a Martian counterpart to Earth’s geoglyphs—a deliberate creation by an intelligent civilization? The idea echoes Gauss’s dream of a geometric signal, designed to be seen from afar. If this structure is artificial, it raises profound questions: Who built it? Was it meant to mark territory, commemorate a ritual, or signal to the stars?
The Archaeology, Anthropology, and Interstellar Communication report urges caution. Alien artifacts might blend seamlessly with natural features, making them hard to identify. Yet the keyhole’s striking form invites speculation. Is it a relic of a long-lost Martian culture, or perhaps a marker left by visitors from another world? As we continue to explore Mars, each new image brings us closer to answering whether this enigmatic structure is a natural oddity—or humanity’s first glimpse of alien design.
