This Franco-German-Spanish project had three main objectives: -an environmental objective: through interventions during the project, the young people were able to discover, debate, exchange and deepen their knowledge of the impact of global warming on the planet, particularly on marine waters, to raise awareness of environmental problems on the coast and to discover solutions that are being implemented. -a physical and mental objective: together, the young people hiked dozens of kilometers along the GR34. They were able to challenge themselves, improve their physical abilities, and discover the impact of sport, particularly walking, on our mental health and physical well-being. -An intercultural objective and a desire to live together: the main challenge of this exchange was, of course, interculturality and living together. Over a ten-day period, participants from 3 different nationalities had to learn to live together, to respect each other, to respect each other's rhythms, to find consensus, to cook together, to set up camps and dismantle them while roaming on the GR34, and all this after a day's hiking. Cross-cutting objectives were also present throughout the different activities, such as the development of digital skills with the work carried out before and after the activity, in terms of disseminating results, organizational and logistical objectives: the young people had to succeed in setting up the camps, making a shopping list together, drawing up menus, using equipment (gas stove, cool box, tents...)...