Poster of the EM course in Naples with marine samples. The Electron Microscopy Hands-On Course: sample preparation and imaging of marine environmental samples arises from a very strong and active collaboration between the Stazione Zoologica Anton Dohrn and the EMBL in Heidelberg. The aim of the course is to provide a theoretical and practical training on electron microscopy starting from the basics to the preparation of samples with high pressure freezing and image acquisition using TEM and SEM.