Located in the courtyard of the upmarket Quadrio shopping centre above Národní třída metro station, David Černý's giant rotating bust of Franz Kafka is formed from 39 tonnes of mirrored stainless steel. It's a mesmerising show as Kafka's face rhythmically dissolves and re-emerges, possibly playing on notions of the author's ever-changing personality and sense of self-doubt. Many stand for ages watching the spectacle.