NASA’s Curiosity rover has discovered an extraordinary expanse of honeycomb-like formations covering the floor of a Martian valley, giving scientists a new geological mystery to investigate nearly 14 years after the spacecraft landed on Mars.

The geometric features, known as polygonal fractures, were found as Curiosity climbed through an area informally called Valle Grande on the slopes of Mount Sharp inside Gale Crater. 

Although the rover has encountered similar polygons during its long exploration of Mars, NASA scientists say they have never seen them concentrated across such an extensive area.

The discovery could help researchers reconstruct the history of water and climate on Mars. Scientists are considering several explanations for the unusual terrain, including ancient mud that repeatedly dried and cracked, temperature-driven expansion and contraction, and pressure on buried sediments that forced water from the rock.

For now, NASA says the origin remains unresolved.

Curiosity Rover Sea of Polygons on Mars

Curiosity photographed the remarkable landscape while traveling through Valle Grande in June. A 360-degree panorama assembled from images captured June 19 and 20 — mission sols 4,930 and 4,931 — shows polygons spreading across the terrain in multiple directions.

The individual formations are generally only a few inches across. NASA described the honeycomb-like features as polygonal fractures about 1.5 to 3 inches, or 4 to 8 centimeters, wide. The patterns continue around a nearby butte nicknamed Miraflores, which rises about 20 feet above the surrounding landscape and is capped by sand.

Scientists had seen polygon-rich terrain before. In May 2025, Curiosity encountered particularly well-preserved fractures with raised ridges about 0.39 inches high. 

By April 2026, the rover was traveling across terrain where thousands of honeycomb-shaped polygons stretched for meters.

Valle Grande, however, has taken the phenomenon to another level.

Scientists Search for an Explanation

Polygonal terrain can form through several geological processes, meaning the honeycomb appearance alone cannot establish what happened at Valle Grande billions of years ago.

One possibility is desiccation, in which wet, muddy sediment shrinks and cracks as it dries. Such an explanation would be particularly significant because it could provide additional evidence that water once existed at the site.

Scientists also are considering whether repeated heating and cooling fractured the surface or whether the features developed after sediment was buried and compressed, squeezing water from the material.

Those possibilities tell different stories about ancient Mars. Determining which process occurred could reveal whether Valle Grande once experienced surface water, subsurface water or environmental conditions unrelated to liquid water.

Curiosity previously found polygonal patterns elsewhere in Gale Crater, including features scientists have investigated as possible evidence of ancient wet-dry cycles and groundwater activity.

Curiosity Rover Instruments Investigate the Honeycomb Terrain

NASA is using Curiosity's scientific instruments to examine both the raised polygon ridges and the material inside them.

The rover's ChemCam, or Chemistry and Camera instrument, can fire a laser at Martian rocks and analyze the resulting plasma to determine their chemical composition. 

The Alpha Particle X-Ray Spectrometer, or APXS, measures the elemental chemistry of rocks and soil, while the Mars Hand Lens Imager, or MAHLI, produces close-up images of geological targets.

During its investigation of the polygon-covered region, the mission team directed APXS and MAHLI toward the ridges and centers of polygons. ChemCam measurements also targeted multiple ridges and a polygon center, allowing researchers to compare their composition.

Chemical differences between the ridges and their interiors may help scientists determine whether minerals were deposited by water after fractures formed or whether the structures developed through another mechanism.

Curiosity Rover Continues a 14-Year Mars Mission

Curiosity landed inside Gale Crater on Aug. 5, 2012, beginning a mission designed to investigate whether ancient Mars ever offered environmental conditions suitable for microbial life.

The car-sized rover has spent much of its mission exploring Mount Sharp, a roughly 3-mile-high mountain rising from the center of Gale Crater. Curiosity began ascending the mountain in 2014, examining progressively younger and different geological layers along the way.

The terrain tells the story. 

Today, Mars is a dramatically changing planet. It is cold, dry, rocky and covered in a thin atmosphere dominated by carbon dioxide.

Its surface includes enormous volcanoes, impact craters, dunes, canyons, rocky plains and polar ice caps. But geological evidence shows ancient Mars was considerably wetter, with rivers, streams and lakes existing during parts of its early history.

Gale Crater itself preserves evidence of ancient lakes. At the same time, Mount Sharp's layered rocks provide a geological record of changing conditions as Mars evolved from a wetter world into the arid planet seen today.

Curiosity's continuing climb allows scientists to study that transition layer by layer.

Why the Martian Honeycomb Field Matters

The mystery of Valle Grande is important because the formations may preserve another piece of Mars' water history.

Water is central to Curiosity's mission because environments containing persistent liquid water could have been potentially habitable for microbial organisms. The rover is not designed to find living organisms, but it can identify geological and chemical evidence showing whether ancient environments possessed conditions that could have supported life.

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Earlier investigations have already shown that Gale Crater contained environments favorable to habitability billions of years ago.

The newly discovered polygons could add another chapter to that history — but scientists first need to determine how they formed.

The scale of the Valle Grande field makes the discovery particularly unusual. After thousands of Martian days traveling across Gale Crater, Curiosity has encountered another landscape unlike anything it previously examined.

Data from ChemCam, APXS, MAHLI and Curiosity's cameras may eventually reveal whether the vast honeycomb field is the fingerprint of ancient water, extreme environmental cycles or geological forces operating beneath the Martian surface.

For now, the strange geometry remains another unanswered question preserved in the rocks of Mars.

More Information

NASA — Curiosity Mars Rover Discovers Field of Honeycomb Textures

NASA JPL — Curiosity Rover Honeycomb Discovery

Popular Science — Curiosity Rover Spots Ancient Sea of Martian Polygons

Phys.org — Curiosity Mars Rover Discovers Field of Honeycomb Textures

Tech Times — Curiosity Finds Mars Honeycomb Field

Geek Spin — NASA Rover Finds Massive Honeycomb Patterns on Mars