Planets / Geology

How Do You Build A Volcano 22 km Tall? Ask Mars

2026-08-13
Enjoyed the clip?
A new space fact every day — follow so you never miss one.

Mars built a volcano so wide it would swallow a country.

Mars built a volcano so wide it would swallow a country. Olympus Mons stretches roughly 600 kilometres across its base — drop it over France and it would cover the entire nation. Rise up from that base and you climb about 22 kilometres before you reach the summit. That is two and a half times the height of Everest. What allowed this to grow so enormous? Two things, working together over billions of years. Mars has weaker gravity than Earth, so lava can pile higher before it collapses under its own weight. And Mars has no moving tectonic plates, so the crust sat still above the same hotspot, letting layer after layer of runny lava quietly stack up. No explosive blasts. No drama. Just slow, patient, geological patience — and the result is the largest volcano we have ever found anywhere in the solar system. Follow Deep Field Vault for more of the universe.

OLYMPUS MONS

  • Largest volcano
  • in the solar system

600 KM WIDE

  • Big enough to
  • cover an entire country

22 KM TALL

  • 2.5× the height
  • of Everest

WHY SO BIG?

  • Low gravity
  • No tectonic plates
  • Lava stacked for billions of years

SHIELD VOLCANO

  • Runny lava
  • Not explosive eruptions
Imagery: NASA / NASA/JPL/Malin Space Science Systems (public domain) · View original on NASA ↗
Follow Deep Field Vault
A new space fact every day — follow so you never miss one.