Grjótagjá Cave. Geothermal Cave. Near Mývatn. By Norris Niman. North Iceland. Grjotagja Cave. Posted on October 10, 2022October 10, 2022 1440 × 960 Grjótagjá Cave. Geothermal Cave. Near Mývatn. By Norris Niman. North Iceland. Grjotagja Cave. Grjótagjá Cave. Geothermal Cave. Near Mývatn. By Norris Niman. North Iceland. Grjotagja Cave.