Augmented Reality reveals sculptures invisible to the naked eye in a curious art show installed on the banks of London's Thames river. Scan a QR code plastered to several red life buoys with a phone or tablet, and giant, colourful digital sculptures, some of them hovering above the river, come to life on the screen. With museums closed across the United Kingdom because of coronavirus restrictions, the exhibition, called "Unreal City", provides a safe, "dematerialised" way of enjoying art in the public sphere, explains the show’s curator, Daniel Birnbaum.