On Horses by Mount Herdubreid / Á hestum undir Herðubreið Herðubreið (broad-shouldered) is a tuya in north-east Iceland. It is situated in the Highlands of Iceland in the midst of the Ódáðahraun desert and close to Askja volcano. The desert is a large lava field originating from eruptions of Trölladyngja. Herðubreið was formed beneath the icesheet that covered Iceland during the last glacial period.