How dirt matters to the future of cities There is a world full of life beneath our feet. Hidden in the soil, up to 100 million species of micro-organisms work together with fungi and plant roots to form networks that ensure a healthy living environment. Without soil, we cannot survive. Yet in the city we treat our living environment inattentively, even as patterns of migration from country to city continue to increase, annexing surrounding areas and literally squeezing the life out of the soil. The urban climate, urbanized environment and urban water balance are detrimental to healthy soil life: soil is largely sealed off in urban circumstances, resulting in extreme flooding, heat and drought exhaustion, soil compaction and habitat fragmentation. BiodiverCITY represents a quest for biodiversity in the city. How do you design a public space that is anchored in healthy soil? The contributors to this volume formulate measures that can produce healthy soil life.