While being on a picnic, if you are not sure whether you brought the boiled or the raw eggs in your basket, there is a simple way of telling without smashing them open: Simply spin them. The boiled egg will spin very fast when you rotate it, whereas the raw egg will resist the spinning motion. Nuclear physicists make nuclei spin to study their internal features. Some 50 years ago a most astonishing effect was observed in rapidly rotating nuclei. This surprise discovery, known as backbending, which is a unique phenomenon in the finite, many-body quantum system, triggered a revolution of our studies into the structure of the atomic nucleus that continues to the present day.