A short distance from Lake Mývatn you’ll find the geothermal power center of Krafla. Its name derives form the mountain Krafla (818 m).
It’s possible to drive a “dead end” road through the area which climbs steeply up to the Krafla caldera. What is a caldera? A Caldera is made when the roof of the magma chamber collapses after the chamber has been emptied by an explosion.
There is a special parking area and you can take a short walk to the edge of the caldera or even walk along a path to the left which will take you to a lava field in about an hour.
Photo above:
This Wikipedia and Wikimedia Commons image is from the user Chris 73 and is freely available at http://commons.wikimedia.org/wiki/Image:Lava_at_Vulkan_Krafla_Iceland_1.JPG under the creative commons cc-by-sa 2.5 license.
