Stromboli (Italy)
One of Earth's most active volcanoes
It erupts nearly continuously
Local people have learnt to live with the constant but mostly mild eruptions
Other volcanoes can be deadly
Nevado Del Ruiz (Columbia)
Erupted November 1985
Mudslides killed 25,000 people
Another potential disaster is waiting to happen
Yellowstone National Park Wyoming, USA
A dormant supervolcano
Area 3960 km2
Threatens to erupt
When it does
North America could be completely devastated
Its ash will blot out the Sun worldwide for a decade
Last erupted 640,000 years ago
When will it erupt again?
No one knows