This paper presents a review of the high altitude EMP (HEMP) activities in European countries between 1970 and 1995. HEMP simulators built in different countries are presented together with measurements performed under them and calculation methods developed in order to simulate the currents or voltages induced by an HEMP in power or telecommunication lines or in other types of circuits. Comparison between calculations and measurements are shown. This paper focuses on this period, which was of historical importance for the hardening of vital military and governmental installations, but which permitted also the development and validation of models to study the electromagnetic effects of lightning.