Geysir, Haukadalur Valley, Iceland, 2010. Actually, Geysir (from which derives the English word geyser) is not so active these days; the pictures show the nearby Strokkur geyser, which erupts every 20 minutes or so. The eruption is preceded by a short-lived blue dome. The four pictures shown here are not all the same eruption. The blue dome in particular was somewhat hard to photograph.