According to the United States Geologic Survey, there are approximately 1,500 potentially active volcanoes worldwide. Most are located around the Pacific Ocean in what is commonly called the Ring of Fire. A volcano is defined as an opening in the Earth's crust through which lava, ash, and gases erupt. The term also includes the cone-shaped landform built by repeated eruptions over time.

A conical volcano formed after volcanic eruption

Luzon, the Philippines — the world's most perfect volcanic cone