From Earth, Mars appears as a small red point of light. Seen close up, however, its rocky, dust-covered surface contains some of the largest and most dramatic landforms in the solar system. Enormous volcanoes, canyon systems, impact basins, polar ice caps and dried river channels record a long history of impacts, volcanic activity, wind erosion and flowing water.
The planet’s familiar red color comes from iron minerals in its rocks and dust that have oxidized, or rusted. Beneath this widespread covering, Mars preserves landscapes ranging from ancient cratered highlands to broad volcanic plains and regions where rivers and lakes existed billions of years ago. The following ten features reveal the scale and geological variety of the Martian surface.
What Is the Surface of Mars Like?
The global elevation map above reveals Mars’s most fundamental geographical division. Blue represents the younger, smoother northern lowlands, while red and white show the older, elevated and heavily cratered southern highlands. The labels provide a reference for the ten major features explored below.
Known as the Martian hemispheric dichotomy, this contrast reaches several kilometers in elevation. Its origin remains uncertain, although proposed explanations include internal geological processes, one or more colossal impacts, or a combination of both.
1. Tharsis Rise: Mars’s Enormous Volcanic Plateau
Nearly a quarter of Mars’s surface is dominated by a single feature: the Tharsis Rise, a vast elevated region of volcanic terrain stretching roughly 3,100 miles (5,000 kilometers) across the planet’s western hemisphere. It was built by repeated volcanic activity over billions of years and rises several kilometers above the surrounding plains.
The region contains four major shield volcanoes. Ascraeus Mons, Pavonis Mons and Arsia Mons form a broad northeast-to-southwest line known as the Tharsis Montes, while Olympus Mons stands farther to the northwest. The immense growth of Tharsis placed the surrounding crust under great stress, helping create extensive fractures and contributing to the development of Valles Marineris along the plateau’s eastern side.
2. Olympus Mons: The Solar System’s Largest Volcano
Rising about 16 miles (25 kilometers) above the surrounding plains, Olympus Mons is nearly three times the height of Mount Everest above sea level. Mars’s tallest mountain is also the largest known volcano in the solar system, extending roughly 370 miles (600 kilometers) across. Its summit caldera consists of several overlapping collapse pits created as underground magma chambers emptied.
The mountain is a shield volcano built by repeated flows of fluid lava, giving it broad, gently sloping sides rather than the steep profile of a cone-shaped volcano. Around much of its base, however, Olympus Mons ends in a steep escarpment rising several miles above the surrounding plains, giving the volcano an unusually abrupt outer edge.
Mars’s lower gravity helped Olympus Mons grow to an exceptional size, while the absence of Earth-like plate tectonics allowed volcanic activity to remain concentrated in the same region for immense periods. Some lava flows on the volcano are geologically young, although no eruption has ever been observed.
3. Syrtis Major: A Dark Volcanic Region Visible From Earth
Long before spacecraft reached Mars, early astronomers could see Syrtis Major through their telescopes as a broad, dark marking on the planet’s surface. Stretching roughly 930 miles (1,500 kilometers) from north to south near the boundary between Mars’s northern lowlands and southern highlands, it was initially assumed to be a dark-colored plain. Spacecraft observations later revealed that the region is an ancient volcanic province dominated by basaltic material.
Winds have removed much of the brighter red dust from its surface, exposing darker volcanic rock beneath. This strong contrast makes Syrtis Major one of the most recognizable Martian features through Earth-based telescopes. Christiaan Huygens drew it in 1659 and used its movement across the planet’s face to make one of the earliest estimates of the length of a Martian day.
4. Valles Marineris: The Solar System’s Largest Canyon System
Seen from orbit, Valles Marineris resembles a vast crack in the Martian surface, extending about 2,500 miles (4,000 kilometers) along the equatorial region. Roughly as long as the United States is wide, this interconnected canyon system widens to hundreds of miles in places and descends more than 5 miles (8 kilometers) from rim to floor, making it the largest known canyon system in the solar system.
Unlike Earth’s Grand Canyon, Valles Marineris was not created primarily by a river cutting through rock. Much of the system began when the Martian crust stretched and fractured as the neighboring Tharsis region developed. Landslides, erosion and flowing water later modified parts of the canyon, exposing layered rocks that preserve a long record of Mars’s geological history.
5. Hellas Planitia: A Vast and Deep Impact Basin
Around four billion years ago, an enormous impact struck Mars’s southern highlands. The resulting Hellas basin spans roughly 1,400 miles (2,300 kilometers), making it one of the largest clearly visible impact structures in the solar system. Its floor lies more than 4 miles (7 kilometers) below the average Martian surface, while the surrounding terrain rises high above it.
This exceptional depth gives Hellas a higher atmospheric pressure than most other locations on Mars, allowing frost, clouds and windblown dust to collect within it. The impact also excavated and disrupted vast quantities of crust, leaving a planetary-scale scar that remains conspicuous even in global views of Mars.
6. Vastitas Borealis: The Great Northern Lowland
If Mars once possessed a northern ocean, much of it may have covered Vastitas Borealis, the broad, low-lying plain surrounding the planet’s north polar region. Its relatively smooth surface contrasts sharply with the older and more heavily cratered southern highlands. Lava flows, sediments, ice-related processes and windblown material have all helped shape and partly bury the region’s earlier terrain.
Several immense channels carved by ancient floods descend toward these northern plains. Possible shorelines and water-related deposits have also been interpreted as evidence of a former ocean, but the idea remains debated because many proposed coastal features are discontinuous or occur at different elevations. Whether or not a long-lived ocean existed, Vastitas Borealis preserves evidence that large quantities of water and sediment once moved into Mars’s northern lowlands.
7. Utopia Planitia: A Plain Hiding Buried Water Ice
Hidden beneath parts of Utopia Planitia are extensive deposits of water ice. The broad plain lies within a huge, largely buried impact basin in Mars’s northern hemisphere, where polygonal patterns and shallow depressions provide surface evidence of ice-rich ground.
Radar observations by NASA’s Mars Reconnaissance Orbiter have revealed a large subsurface deposit beneath a relatively thin covering of soil. In places, the ice-rich layer may extend hundreds of feet below the surface.
The ice may have accumulated when long-term changes in Mars’s axial tilt allowed snow or surface ice to form much farther from the poles before it was buried by dust and soil. Utopia Planitia has also been explored directly: Viking 2 landed there in 1976, followed by China’s Zhurong rover in 2021.
8. The Martian Polar Caps: Layers of Water and Carbon Dioxide Ice
For a world known for its dry, dusty surface, Mars stores immense quantities of water ice at its poles. During each Martian winter, carbon dioxide from the planet’s thin atmosphere freezes onto the polar regions as dry ice. The seasonal caps spread across the surrounding terrain before retreating again in spring as the carbon dioxide changes directly from solid back into gas.
The northern residual cap is predominantly water ice, while the smaller southern cap retains permanent carbon dioxide ice as well as extensive water-ice deposits. Both polar regions contain layered deposits of ice and dust accumulated over millions of years. Their alternating bands preserve evidence of past climate cycles caused by long-term changes in Mars’s orbit and axial tilt.
Broad spiral troughs cut across the layered northern cap, creating one of the most distinctive patterns on the Martian surface. Their form developed as winds eroded and redistributed ice and dust while new layers accumulated over time.
9. Gale Crater and Mount Sharp: A Record of Ancient Environments
Near the Martian equator, the 96-mile-wide (154-kilometer) Gale Crater contains a mountain rising about 3 miles (5 kilometers) above its floor. Known as Mount Sharp—and officially as Aeolis Mons—its exposed layers of rock record changing conditions over an immense span of time, making Gale one of the most valuable locations for reconstructing Mars’s environmental history.
NASA’s Curiosity rover has explored the crater since 2012. It has found rounded pebbles deposited by ancient streams, mudstones formed in long-lived lakes and minerals produced through interaction with water. These discoveries show that Gale once contained environments that could have been habitable for microbial life, although they do not demonstrate that life actually existed there.
Curiosity has also examined the dark Bagnold Dunes along the lower slopes of Mount Sharp. These active sand dunes migrate as Martian winds move grains up their shallower sides and down their steeper faces, demonstrating that Mars’s surface continues to change today.
10. Jezero Crater: An Ancient Lake and River Delta
Billions of years ago, a river flowed through a break in the rim of Jezero Crater and emptied into a lake, depositing sediment in a fan-shaped delta. The 28-mile-wide (45-kilometer) impact basin also has another channel through which water once flowed out. Together, these features provide some of the clearest surface evidence that stable bodies of liquid water existed on early Mars.
The delta contains clay minerals and other materials capable of preserving organic compounds and possible microscopic evidence of past environments. NASA selected Jezero as the landing site for the Perseverance rover, which arrived in 2021 to study its rocks, reconstruct the crater’s history and collect samples for possible return to Earth. Jezero therefore connects a landscape formed billions of years ago with the continuing effort to determine whether Mars ever supported life.