As of 2020, the physical mass of all the world’s man-made structures exceeded that of all the world’s living things. And there’s raw materials – sand and construction minerals - at the heart of these structures, but we rarely notice them, or think about where they come from. In this episode we speak with Dr Aurora Torres, one of the leading experts in the sustainability implications of society’s hunger for sand and construction minerals, and explore the ecological economics of the sand supply networks that underpin most of contemporary society. Edited by Aidan Knox.