Volcanoes almost anywhere in the world can awaken and erupt violently, even after being dormant for thousands of years. Although some eruptions are short-lived, others can go on for a long time. Volcanoes are not scattered randomly around the world; they are generally located in areas where Earthˇs crust is broken or where magma has managed to pierce it. The Ring of Fire, which circles the Pacific Ocean, counts for about 80 percent of the volcanoes in the world. These mountains of fire provide us with the only opportunity to directly study the different materials that make up the interior of our planet. Thanks to continuous observation by the scientists who study them, who are called volcanologists, it is becoming easier to predict eruptions and to evacuate people from a dangerous area before itˇs too late.