Let's start with a big question: what are the pillars of civilisation? There are a few possible answers, but our guests today might argue that the list should include soil. Humble, dirty dirt, crawling with larvae, fungus and bacteria is an under-appreciated champion because, without it, we would not be here. To celebrate the magic of soils, Sophia Dacy-Cole has just submitted her PhD which includes an exhibition that celebrates soil (Instagram and website). Joining us is Dr Alex Wall, a paleoecologist from the ANU. We want to know more about paleoecology; stay tuned. Interview by Lucy and Rod.