Dimmuborgir was formed in an eruption that occurred
in the area 2,300 years ago.
As lava flowed across the area, it passed over a lake, causing it to boil. This both quickened the cooling of the lava and caused pillars of steam to shatter parts of it. After it solidified, Dimmuborgir area became defined by large stacks of rock and many caves and caverns, caused by bubbles of intense steam.
As such, many have compared Dimmuborgir to a medieval castle, with its many hidden chambers and its rising towers.