Dimmuborgir

Dimmuborgir (dimmu "dark", borgir "cities"[1] or "forts", "castles"; pronounced [ˈtɪmːʏˌpɔrcɪr̥]) is a large area of unusually shaped lava fields east of Mývatn in Iceland.

The Dimmuborgir area is composed of various volcanic caves and rock formations, reminiscent of an ancient collapsed citadel (hence the name).

The area is characterised by large hollow cell- or chamber-like structures formed around bubbles of vapour, and some dramatically standing lava pillars.

Several of the chambers and pillar bases are large enough to house humans, giving rise to the term "castles" (borgir).

In Nordic Christian lore, it is also said that Dimmuborgir is the place where Satan landed when he was cast from the heavens and created the apparent "Helvetes katakomber" which is Norwegian for "The Catacombs of Hell".

Dimmuborgir, the "Dark Castles"
Kirkjan ("the Church"), lava tube structure at Dimmuborgir