The project “Warning! The big planetary threats: knowing them to defend ourselves” aimed to develop interdisciplinary educational paths on the themes of environmental fragility and danger, addressing a wide audience but with a specific focus on young people. The initiative consisted of 5 debates were scientists presented an in-depth scientific analysis of so-called natural disasters, i.e. phenomena related to climate change, major pandemics, endogenous events (i.e. volcanoes and earthquakes), the fall on the earth's surface of asteroids and space debris and finally to the pollution of the seas, and their consequences. The aim was to foster a “culture of being ready” consisting in the adoption of responsible and scientifically sound behaviors, overcoming a culture dominated by the “here and now” and therefore little motivated to tackle long-term problems. All the considered phenomena have decidedly complex characteristics: the unpredictability or difficult predictability of their development, the quantification of the risks, the dangerous interconnections among them, the increasingly global nature of their effects and the diversity of their impact according to the social, economic and even cultural situations in the various geographical areas. The debates underlined the importance of internationally supportive initiatives to address these dangers. An interdisciplinary approach was used stressing the importance of the scientific method to face complex problems. Physics was the “fil rouge” accompanying the participants in this journey across many fields of science. The various events took place virtually, allowing the participation of more than 3000 high school students from about 20 schools. To encourage the conscious and direct participation of students in the debate, explanatory material provided in digital form was made available to interested teachers. Students were asked to present their questions to the speakers in advance, therefore a significant part of the seminars was devoted to answering student questions. “Warning” represented a useful educational support for students and teachers, who were able to attend the events in a “virtual classroom”, and integrate topics covered in school programs.