ABSTRACT
This chapter provides a comprehensive view of the research in geometry education that has been presented during Congress of European Research in Mathematics Education (CERME) conferences. It focuses on the close link between theoretical and empirical aspects that has always guided the researchers of the group. The chapter discusses some methodological and theoretical tools developed within the group are introduced and shows how the constituted a common support for studies in the field. It focuses on the main findings from the group are given by emphasising the spirit of communication and collaboration built up through the different meetings. The chapter traces a common research agenda is considered that could be organised to achieve a deeper understanding of geometrical thinking and competencies through the whole education. Geometry is traditionally viewed as a work on geometrical configurations which are both tangible signs and abstract mathematical objects.
