The star on the map shows the location of the Eyjafjallajökull glacier which covers an active volcano that erupted on 20 March and 14 April of 2010. The latter eruption caused enough volcanic ash to spew into the jet stream that airline flights were canceled all over Europe.
Iceland is sitting in a large volcanic hot spot. More about the volcanoes of Iceland and a couple of geologic volcano maps can be found at Volcanoes of Iceland.
A history of the Eyjafjallajökull Eruptions is updated frequently on Wikipedia.
If you're looking for a map of Iceland cities, see our Iceland Travel Map.