Volcano researcher at the glowing throat of Pacaya volcano, a complex basaltic volcano just outside Guatemala City in Guatemala. It is one of the country's most active volcanoes. During the last several decades it has exhibited frequent Strombolian eruptions and occasional lava flows with occasional powerful eruptions. This view shows an active vent in MacKenney cone, which was exposed after an eruption destroyed the surrounding cone, the remains of which are seen here. Photographed July 2005.