Mount Sinabung spews pyroclastic smoke as seen from Tigapancur village in Karo district on November 2013 in Medan, Sumatra, Indonesia. Up to residents have been evacuated from five villages in North Sumatra due to the volcanic eruptions of Mount Sinabung.
The mountain-like mounds that we associate with volcanoes are what remain after the material spewed during eruptions has collected and hardened around the vent. This can happen over a period of weeks or many millions of years.
The Old Fire crossed Highway 18 near Lake Arrowhead, California on 28 October 2003 before racing into the community of Cedar Glen as a crown fire and destroying most of the homes there. photo source: Firestorm from NationalGeographic
Kawah Ijen volcano in Indonesia: "This blue glow, unusual for a volcano, isn't the lava itself, as unfortunately can be read on many websites. It is due to the combustion of sulfuric gases in contact with air temperatures above ~Smithsonian Magazine
Arenal Volcano, Costa Rica, viewed from the northwest. Volcan Arenal is the youngest—under years old—and most active of all the volcanic mountains in Costa Rica. Presumed extinct until a 1968 earthquake re-awakened it, the mountain now produces regu