This is the virtual reality preparation app for children undergoing surgery. In this app you can look around the operating room and get more information about how you will be put to sleep. The app was developed by the Department of Child and Adolescent Psychiatry and Anesthesiology at the Erasmus MC – Sophia Children's Hospital. Currently, the app can only be used by children participating in scientific research at Erasmus MC and Maasstad Hospital. Children who participate receive a code for this. We hope to make this app available to everyone soon after the research has been completed.