This work discusses a didactic path aimed at revisiting the first experiments on the transmission and detection of electromagnetic waves, performed by Guglielmo Marconi at the end of the 19th century. With very simple materials it is possible to set-up apparatus that allow to illustrate practically the simple physical picture of wireless telegraphy, and in particular the role of monopole antennas and ground connections, first introduced by Guglielmo Marconi to increase the distance between the transmitter and the receiver. Retracing in the classroom the first steps of the beginning and the advent of radio communications is important for both science education and the students' understanding of the connected world we live in.