Collaboration is mentioned by the UNESCO as one of the key competences for reaching sustainable development. Within our project students will work together on the topics of quality of life and sustainability. An international collaboration with students from a different socio-cultural background should enable a reflection about the teenagers' personal concepts and the joint development of new concepts which take inter- and intragenerational justice into consideration. The project follows a moderate-constructivist learning setting in which teenagers collaborate in conducting research and present and disuss the results via eTwinning.