Lava caves

thumb|Grjótagjá cave in summer 2009 thumb|Landscape above Grjótagjá cave Grjótagjá () is a small lava cave near lake Mývatn in Iceland. It has a thermal spring inside.

Cave in Icod de los Vinos, Northern Tenerife

cave formed in volcanic rock, especially one formed via volcanic processes

mountain cave on the island of Réunion