Drag the vertical-exaggeration slider to see why Olympus Mons still looks like a gentle dome at true scale, then toggle the Everest and Mauna Loa columns to compare heights side-by-side.
Olympus Mons is the largest known volcano in the solar system: NASA's Mars Atlas cites a base diameter of about 624 km and a summit roughly 25 km above the surrounding plains, with an 80 km wide caldera complex at the top. Mars has no plate tectonics and only about 38% of Earth's surface gravity, which is why the same hot spot could keep building one shield this large instead of drifting into a chain of smaller ones the way Hawaii's volcanoes did on Earth's moving Pacific Plate.
Drag to orbit and scroll or pinch to zoom. For a whole-planet terrain view instead of one landmark, see the Mars Terrain 3D Explorer; for the low-gravity mechanics that let this shield grow so large, see the Escape Velocity 3D Explorer.
Olympus Mons 3D Explorer
This browser explorer builds a procedural 3D model of Olympus Mons - the largest known volcano in the solar system - from NASA's real published diameter, height, and caldera figures, then lets a reader drag a vertical-exaggeration slider and compare its scale directly against Mount Everest and Mauna Loa.
NASA's Mars Atlas cites a base diameter of about 624 km for Olympus Mons and a summit approximately 25 km above the surrounding plains, with an 80 km wide, roughly 3 km deep caldera complex at the top; other NASA sources cite slightly different summit-height figures (21.9-27 km) depending on whether the reference frame is the surrounding plains or the Mars areoid datum. The shield is so large mainly for two reasons: Mars has no plate tectonics, so the hot spot that fed the volcano never drifted away from the same patch of crust the way Hawaii's hot spot drifts under Earth's moving Pacific Plate, and Mars's surface gravity is only about 38% of Earth's, which lets a shield this wide and tall persist without collapsing under its own weight.
- Drag the vertical-exaggeration slider (1x-8x, default 4x) to see the real slope - at true 1x scale the shield looks almost flat, because it really is that gentle
- Toggle the Everest / Mauna Loa scale-comparison columns on or off
- Click "View caldera from above" to snap the camera to a top-down angle over the caldera complex
- Drag to orbit, scroll or pinch to zoom
- Runs fully in the browser with the vendored three.js engine - no account, no upload
| Feature | Olympus Mons (Mars) | For comparison |
|---|---|---|
| Base diameter | ~624 km (NASA Mars Atlas) | Mauna Loa's above-sea-level dome: ~120 km long x ~103 km wide (Britannica) |
| Summit height above local base | ~25 km above the surrounding plains (NASA; 21.9-27 km depending on reference frame) | Mount Everest: 8.849 km above sea level (2020 Nepal/China survey) - Olympus Mons is roughly 2.8x taller |
| Caldera complex | ~80 km wide, ~3 km deep (up to ~85 km per an alternate NASA source) | Mauna Loa: ~10.211 km from the ocean floor to the summit (U.S. National Park Service) - Olympus Mons is roughly 2.4x taller measured base-to-summit |
| Why it grew this big | No plate tectonics + only ~38% of Earth's surface gravity (NASA) | Earth's shield volcanoes (like Mauna Loa) drift off their hot spot as the plate moves, capping how large any single one can grow |
For a whole-planet terrain view instead of one landmark, open the Mars Terrain 3D Explorer. For the low-gravity mechanics that let a shield like this grow so large without collapsing, open the Escape Velocity 3D Explorer.
Everything renders on your device with WebGL. The 3D engine loads once (about 0.7 MB) and is cached.
This is an educational approximation - the shield and caldera shape are a mathematical profile matched to the real published diameter, height, and caldera figures above, not a survey-grade elevation scan of the actual surface. The base diameter, summit height, caldera size, and the Everest/Mauna Loa comparison figures are the real NASA/USGS/Britannica-published values.
Frequently Asked Questions
How big is Olympus Mons?
NASA's Mars Atlas cites a base diameter of about 624 km and a summit approximately 25 km above the surrounding plains, with an 80 km wide caldera complex at the top.
Why is Olympus Mons so much bigger than Earth's volcanoes?
Mars has no plate tectonics, so the hot spot that fed the volcano never drifted away from the same patch of crust the way Hawaii's hot spot drifts under Earth's moving Pacific Plate. Mars's surface gravity is also only about 38% of Earth's, letting a taller, wider shield form without collapsing under its own weight.
How does Olympus Mons compare to Mount Everest?
Mount Everest is 8.849 km above sea level (2020 Nepal/China survey). Olympus Mons's summit is about 25 km above the surrounding plains - roughly 2.8 times taller.
How does Olympus Mons compare to Mauna Loa?
Mauna Loa, Earth's largest active shield volcano, rises about 10.211 km from the ocean floor to its summit (U.S. National Park Service). Olympus Mons is roughly 2.4 times taller measured the same base-to-summit way, and its 624 km base diameter dwarfs Mauna Loa's roughly 120 km by 103 km above-sea-level footprint.
Why does the volcano look almost flat at 1x exaggeration?
Because it really is that gentle - a 25 km rise spread across a 312 km radius is an extremely shallow slope. The default 4x vertical exaggeration on this page makes the shape and caldera easier to see; the slider discloses exactly how much exaggeration is applied.
Is the 3D shape a real elevation scan?
No - it is a mathematical shield-and-caldera profile matched to the real published diameter, height, and caldera figures, not a survey-grade elevation scan of the actual surface.
How is this different from the Mars Terrain page?
The Mars Terrain 3D Explorer renders a real NASA MOLA elevation heightmap of the whole planet. This page is a dedicated, procedurally-modeled explorer of one specific landmark with a built-in scale comparison against Mount Everest and Mauna Loa.