The main objective of this event was to test different instruments and detectors for the measurements of radon gas and external gamma radiation (dose rate) in real conditions in a place where the levels of natural radiation are quite high (an old uranium mine). The activities carried out consisted not only in the practical exercises but also in different lectures given by intenational experts from different fields of natural radioactivity who are recognized worldwide. A total number of 45 recognised international participant institutions (universities, reference laboratories and commercial companies) took part and this report presents the main results obtained in all the exercises.