With a competent guide, active volcano treks are both safe and worth the climb. Here are some of the tallest active volcanoes ...

Incredible satellite images reveal the moment that Mount Etna, Europe's most active volcano spewed a gigantic plume of ash four miles (6.5km) into the sky.

Mount Etna, on the Italian island of Sicily, erupted last weekend, spewing out high lava fountains and large black clouds of ash and smoke.