"As climate change, overpopulation, and inequalities begin to take their toll on our planet and on global human development, sustainability has become increasingly important for a prosperous future.For the past years, Sustainable Development has been in the EU’s political Agenda. In 2001, the EU established a Sustainable Development Strategy and more recently was a major contributor to the UN’s 2030 Agenda for Sustainable Development.One cannot talk about Sustainable Development without highlighting the role of education. Education is central to the efforts to develop and promote sustainable solutions for the development needs of both people and the planet (UN, 2013).The Education for Sustainable Development (ESD) should be understood as an integral part of quality education and lifelong learning. All educational institutions ranging from preschool to tertiary education and including both non-formal and informal education should consider it their responsibility to address sustainable development and to foster the development of key cross-cutting competencies related to sustainability. (Issues and Trends in ESD, UN, 2018)The project aims to develop an innovative and playful pedagogy for the Sustainable Development education of children (3 to 6 yo) and to raise their interest over STEM. This pedagogy is based on an interactive learning eBook for formal, non-formal and informal learning contexts. Alongside the eBook, it will be produced a guide for educators to facilitate the use of the eBook in learning contexts.Additionally, the project Greenopolis will also deliver:•Project presentations to disseminate the project and the outcomes next to the target groups•Pilot testing activities to test the Greenopolis methodology (Interactive eBook and Facilitator’s Guide), validate it and capacitate educators on ESD •Website and a Facebook page on Education for Sustainable Development with a repository of the materials produced in the project (but not only) and that can be a meeting point for people involved or interested in the topic.•Sustainability Strategy presenting the guidelines for the future exploitation of results and impact of the project.•Contests/Challenges aiming to engage children and educators in the project and to raise awareness towards the Sustainable Development topic•Project Video to promote the Greenopolis eBook.This initiative gathers 5 partners from Poland, Portugal, Greece and Croatia:•SPN (Poland): public elementary school which includes preschool education, working acting as coordinator. •Advancis (Portugal): private company that provides consultancy and training services in Education and People Development, with competences also in ICT based learning methodologies.•BOON (Portugal): private company that provides services in design and illustration.•Center of Education and Entrepreneurship Support (Poland) is a non-governmental, non-profit organization founded in 2004 working in the field of youth, cooperating with businesses, universities, schools, enterprises and educational institutions. •Dječji vrtić ""Radost"" is an Educational Organization with 9 dislocated facilities in which there are 43 educational groups.•EECV is an Environmental Centre from the Education Ministry in Greece, that develops and holds ESD activities for teacher and students, working along with schools."