Ice cave on Mount Erebus
Mt. Erebus is an active volcano on an island in the Ross Sea off of Antarctica. The volcano has been continuously erupting since the early 1970s and hosts one of the few long-lived lava lakes on Earth. The flanks of the mountain are also active, including a variety of fumaroles, places where hot steam and gases released by the magma deep below in the chamber are released into the atmosphere. It is also covered in glaciers as one might expect given its Austral latitude, which are dotted with the occasional spectacular grotto within the frozen water such as the one in the photo.