This is part of the Laki volcano. The Lakagígar are actually a 25 kilometer long row of craters in South Iceland. They were formed in an eruption that went on in the years 1783-1784. The lava flow from this fissure is the greatest flow of lava that has flowed in historical times on Planet Earth. Around 12 cubic kilometers of lava flowed over 580 square kilometers of land.
The period during and after this eruption is perhaps the hardest time in Icelandic history. Very few people were killed directly by the eruption, but about 10.000 people (20% of the population) were killed in the famine that resulted of 80% of sheep dieing, 60% of horses and 50% of cattle.
The effects were not only in Iceland. The ash cloud had a worldwide effect causing crops to fail all over Europe. The University of Cambridge estimates that 10.000 people in England died as a result. Effects were also strong in France potentially adding to the effects that caused the French Revolution.