Compared to the length of a human life, huge volcanic eruptions are relatively rare. However, the impacts of former catastrophes reveal a lot of information for our future. Threat of plague, traces of sulphur in Greenland’s ice, and people vanished for ever – has this to do with volcanoes? Scientists reconstruct former volcanic eruptions and give an insight into the processes in the bowels of the earth. Seismic measurements, observations from the air and chemical analysis shall help to predict the time of a new eruption. However, is a complex society with high techniques really better prepared for the event of a catastrophe?