Situated in the Haukadalur valley, Geysir is by far the most visited geothermal region in Iceland. Extending over 3km2, the area is home to hot-water springs, multicoloured crystals, billowing steam and bubbling pools of mud. And yet visitors notice little of this, as most of them head straight to the stars of the show - the geysers. The Great Geysir, which projects a 15-25m column of water at irregular intervals, is now surpassed by the Strokkur which reaches heights of 20-35m. A thrilling show.