How tall should one design an embankment so that the sea reaches this level only once in 100 years? How large might a possible stock market crash be tomorrow? Many real life questions require estimation, but since no data or only few has been observed – as by definition extreme events are rare – essential estimations are more often based on feeling than on fact. Extreme Value Theory (EVT) is a branch of statistics that deals with such rare situations and that gives a scientific alternative to pure guesswork. In this white paper we show how Extreme Value Theory can literally save your neck.