The largest volcano in our solar system is Olympus Mons, located on Mars. It also is the tallest mountain, reaching a height of about 17 miles (27 km) above the planet's surface. That's about three times as tall as Mount Everest, the tallest mountain on Earth.
More fire mountain facts:
- The biggest volcano on Earth is the Mauna Loa volcano in Hawaii. It reaches about 13,000 feet (about 4,000 meters) above sea level. Though the biggest, it isn't the tallest — the tallest is its neighbor the Mauna Kea at 13,802 feet (4,207 meters).
- The biggest volcanic eruption — with witnesses — was recorded in 1815 when Mount Tambora in Indonesia exploded, killing about 100,000 people.
- The most active volcano in the world is Mount Etna in Italy. It also has the longest period of active documented eruptions, dating back to 1500 BC. The first eruptions happened about a half a million years ago.
- Volcanic rock is the only rock that can float in water.