Dimmuborgir is a very peculiar lava formation. A pool of lava, about 2 kilometers in diameter, formed there during an eruption in "Ludentarborgir". This pool later drained in the direction of lake Myvatn, leaving behind high pillars of lava. It is believed that these pillars were formed in the pool when steam rose through the molten lava and cooled it.
        The sinking surface also coated the pillars with lava slag, which can be seen in many places as a thin coating with vertical etchings. Lava formations like Dimmuborgir have been found off the coast of Mexico, but are not known to exist on dry land anywhere but here.
        Dimmuborgir ("dark cities" or "dark forts") is a large area of unusually shaped lava fields east of Myvatn in Iceland. The Dimmuborgir area is composed of various caves and rock formations, remnants of volcanic activity that are perhaps reminiscent of an ancient collapsed citadel, with columns spewing plumes of sulfuric smoke. In Icelandic folklore the Dimmuborgir is said to connect earth with the infernal regions, and is the purported dwelling-place of elves, trolls, and Santa Clause/Father Christmas.
        Its origin is interesting too: Once this area had been a small lake of damed up lava above some wet underground. When the lava finally flowed off, the chimneys, through which the vapour escaped, and parts of the stiffened cover stayed and became the towers and the gates of the town

        These rock formations accrued about 2,000 years ago when a natural dike stopped a flow of lava. A few parts of the lava flow cooled down and solidified in bizarre forms. These unique lava formations - Dimmuborgir, the ”gloomy castles” – stayed when the dike broke and the still fluid lava could leak.
        A few hiking routes in this area have been marked with different colours, and a leaflet describing them is available from the wardens in the information centre or a box at the main entrance of the area. The “Little Circle” is the route closest to the parking area and takes some 10-15 minutes to walk. The “Big Circle” extends further into the area and takes about half an hour to complete. The “Church Circle” takes about one hour.