This photo is an underground glacier in the Apuseni Park. This is an area of the Carpathian Mountains with over 200 limestone caves. The Focul Viu ice cave that we visited is one of several in Romania. There is about 25 000 cubic metres of ice which has accumulated as snowfall from a large hole in the ceiling of the cave ( along with branches and leaves from the surrounding forest). Due to the poor circulation, cold air sinks into the cave and maintains very low temperatures even in the hot summer months.
An 8 metre ice core has been retrieved from this cave. A piece of wood from 7 metres down was dated at about 1700 years old.