hallmundarhraun lava field
Hallmundarhraun includes the longest and largest caves in Iceland.
Hallmundarhraun lava field was formed in giant eruption close to the Langjökull glacier around the year 930 and is 8-9 cubic kilometers. Hallmundarhraun includes three caves Surtshellir/ Stefánshellir they are together 3500 meters, longest lava cave in Iceland. Viðgelmir lava tube is the largest of all lava caves in Iceland the tubes volume is well over 150,000 cubic meters.