In this paper we present recent work of the physics education group at the University of Pavia, some of which in collaboration with other researchers. The unifying trait of research in Pavia, which the present paper aims to clarify, is its focus on conceptual understanding from a wide perspective, including the design of teaching-learning sequences, studies on teacher professional development, conceptual change research. We discuss three different examples of research directions, all concerning work performed in the past two years