Do we manipulate the darkness, or does it manipulate us? Oxford Professor of Circadian Neuroscience, Russell Foster, explains his research which shows how the blue-tinged sky of dusk is a trigger that tells our bodies it’s time to prepare for bed. Artist Rut Blees Luxemburg finds surprising richness of night-time colours in her photographs, and historian Craig Koslofsky shows how early modern Europeans first colonised the night by introducing street lighting.