This is Hella, a volcano in Iceland. How was it called by Europeans in the Middle Ages?
After the eruption of 1104 stories, probably spread deliberately through Europe by Cistercian monks, told that Hekla was the gateway to Hell. The belief that Hekla was the gate to Hell persisted until the 1800s. Apparently, Jules Verne was inspired by the story. In his "Journey to the Center of the Earth", a path downwards is found inside other Icelandic volcano, Snæfellsjökull.