"The attractive title of the project, starting as a story ""Once upon a time ..."", but emphasizing ""THE SEA"", has become a common denominator for partner schools, located in areas near the Mediterranean Sea, the Black Sea, or the Atlantic Ocean that faces pollution problems. For three years, the marine environment has become a huge learning laboratory for students who have been involved in various activities, all with the main purpose of forming responsible ecological and civic behavior.The project proved to be interesting and attractive due to the activities included in the implementation plan, which stimulated the motivation to explore the sea and its natural attributes from a cultural-artistic perspective. The essence of the project participants' perception about the role they can play in protecting the marine environment emerges from the script of the play entitled ""Traveling with Ulysses"", performed by students from all partner schools, during virtual LTT activities, organized by the school partner from Italy.Digital communication tools have allowed the use of innovative teaching methods that have helped teachers and students to approach the topic of the project, exchanging information in English or their mother tongue, thus stimulating language learning.A lot of students and teachers were involved in the project activities, promoting differentiated learning styles in teaching activities to support students in awareness of the problems facing the marine environment and areas coastal. The proposed activities proved to be very attractive due to their variety: video conferences, transnational seminars, online symposia on various thematic topics (main ports, maritime transport, water sports, biodiversity of marine ecosystems), SEART exhibitions: drawings, paintings, graphics, and mural painting, photography; various art and literary competitions (Sea Poems, The Sea in stories and legends), making decorations using natural marine materials, outdoor activities and greening actions; Sea Cross, Marine Life Carnival, creating of educational games.In the curricular activities complementary to the project theme, innovative methods specific to the students' age were used to stimulate their motivation, creativity, and involvement: task-oriented exercises, discovery, case study, role play, projects, individual and group activities. At the same time, the project brought changes to the curriculum by creating curricula and conducting optional courses (""Children and the Sea"" and ""The Sea from legend to art"").In the process of evaluating the project implementation stage, the degree of completion of the final products, or obtaining feedback on the impact of the product, various tools were used: dialogue, interview, completed online questionnaires, observation or evaluation sheets, reports. All this helped the project teams from the partner schools to establish remedial actions for any dysfunction that occurred during the implementation period.The promotion and dissemination of relevant aspects and results were carried out at the level of partner schools on the occasion of regular meetings of teachers, parents, and students, at the local, regional, or national level, through articles in print, online, news, and TV shows, organization or participation of members project team at various events where leaflets, project information brochures or other promotional materials were distributed to participants.The activities and results of the project were posted in the online spaces dedicated to the project and can be accessed free of charge and unlimited by those interested. All materials created as a result of the project can be considered real educational resources, which can enrich and diversify the range of school teaching materials: a methodological guide for learning activities with students, mini-dictionary and mini-atlas on marine biodiversity, brochures with recipes based on fish and seafood, literary creations of students (poems, stories, legends), educational games, thematic multimedia presentations.We mention that the participants in the LTT activities had the opportunity to get acquainted with various educational systems, to know the cultures of other European peoples, and to contribute to the promotion of the image of the schools of origin at the European level.Also, the entire experience gained will be used for the implementation of other European projects, at a local or regional level. All partners believe that this project and the joint efforts of all parties have contributed to the formation of appropriate behavior for environmental protection, being one of the most important educational factors for the young generation, which will never be forced to say: THE SEA? It was ONCE UPON A TIME..."