Bjarnarflag, 3km east of Reykjahlíð, is an active geothermal area where the earth hisses and bubbles, and steaming vents line the valley. Historically the area has been home to a number of economic ventures attempting to harness the earth’s powers. (Early on, farmers tried growing potatoes here, but these often emerged from the ground already boiled.)
In the 1960s, 25 test holes were bored at Bjarnarflag to ascertain the feasibility of a proposed geothermal power station. One is 2300m deep and the steam still roars out of the pipe at a whopping 200°C.
Later a diatomite plant was set up, but all that remains of the processing plant is the shimmering turquoise pond that the locals have dubbed the ‘Blue Lagoon’. This inviting puddle is actually quite toxic and should not be confused with nearby Mývatn Nature Baths (sometimes called the ‘Blue Lagoon of the North’).