a song of ice and fire. photos by einar rúnar sigurðsson from iceland’s vatnajokull ice caves, which lie bellow a 3,100 cubic kilometre glacier. formed as melt water from geothermal heat and summer temperatures carve through the ice flow, these caverns, subject to glacial motion, are constantly moving and changing shape, and can thus collapse in on explorers at any moment (killing one photographer in 2011). these photos were taken in winter, when the ice is more stable, but when temperatures inside the caves can drop to -120 celcius. (see also: previous posts on glaciospeleology and other caves)