Olympus Mons

Olympus Mons is the biggest volcano we know. It sits on the planet Mars. This volcano is so tall it would tower above any mountain on Earth. It is about three times the height of Mount Everest.

A Super-Sized Volcano

Olympus Mons is about 14 miles high and 370 miles wide. It is shaped like a wide dome with gentle sides. If you walked up the slopes, they would feel pretty flat for a long time. A big crater sits at the very top where lava once came out. The whole volcano is about the size of the state of Arizona.

Why It Got So Big

Mars does not have moving plates in its crust like Earth does. On Earth, plates shift and break up big volcanoes over time. On Mars, lava kept piling up in the same spot for millions of years. That made Olympus Mons grow huge. Scientists think it may still have tiny bits of activity today.

Fun Facts

• Olympus Mons is bigger than the whole chain of Hawaiian volcanoes.
• It was first seen from Earth as a bright spot on Mars.
• The top crater is about 50 miles across.

Did You Know?

Olympus Mons is so wide that if you stood on it, you would not even know you were on a mountain because its slopes are so gentle.