In the early evening, around 20:15, when the sun goes down, the first bats become active and start hunting. Throughout the evening, various types of bat fly above the museum garden and the Jeker. Using a bat detector, you can listen yourself to where the bats are flying and which type they are. The bat detectors pick up the ultrasound noises of these flying mammals and make them audible for the human ear. Bat expert Ger Beckers is on hand to explain it all.