Volcanic activity is a harsh reminder that the world we live in is ever-changing and destructive. Volcanoes are mountains that open downward into a pool of molten rock below earth's surface. When pressure builds, eruptions and disaster occur.

As National Geographic explains, a large eruption can be extremely dangerous for people living near a volcano. Flows of searing lava, which can reach 2,000 degrees Fahrenheit (1,250 degrees Celsius) or more, can be released, burning everything in its path, including whole towns. Orange bursts into the sky, rocks shoot up, and lava rolls down the mountain during a dangerous eruption.

Volcanoes can cause flash floods, tsunamis, mudflows, rockfalls, and earthquakes. Indonesia has become the location of some of the most deadly eruptions. Tens of thousands of lives have been lost to ash flows, mudflows, and tsunamis. More than 80% of the earth's surface is volcanic in origin. The sea floor and some mountains were formed by countless volcanic eruptions. Gaseous emissions from volcano formed the earth's atmosphere (dosomething.org).

According to National Geographic, about 1,900 volcanoes on Earth are considered active, meaning they show some level of activity and are likely to explode again. Many other volcanoes are dormant, showing no current signs of exploding but likely to become active at some point in the future.