In the future of education, concepts of sustainability and recycling have to become integral parts of core subjects which require interdisciplinary collaboration beyond subject borders. Project-based Learning offers the perfect educational environment for such integration of knowledge not limited by single subject curricula or school curricula in general. At the same time, it offers a hands-on approach to actively involve students in the creation of products as well as the training of skills for critical thinking and problem-solving, but also increases their awareness regarding sustainability and environmental challenges. In this context, the goals of a circular economy are supported by such an educational approach combined with an environmental focus.