The role of the civil society and the new generations in countering terrorism, cyber and the new hybrid threats, have been addressed by the 26th annual Symposium organized by the Greek Association for Atlantic and European Cooperation (GAAEC) in Athens during December 13-14, 2017. Key Government and military representatives, together with experts and students participating in the Transatlantic Youth program, took part in the discussion. The Symposium has been opened by the welcome address of Dr. Theodossis Georgiou, President of GAAEC, the introductory remarks of Prof. Fabrizio W. Luciolli, President of ATA, the opening address of Mr. Nikolaos Pappas, Minister of Digital Policy, Media and Telecommunication, and Adm. H.N. Evangelos Apostolakis, Chief of the Hellenic National Defense General Staff.