Symmetries in Quantum Gravity

In this Kolloquium I will highlight the role of symmetries in the investigation of theories of quantum gravity. In particular, I will rely on two consistency conditions: First, theories of quantum gravity do not allow for global symmetries. Second, gauge symmetries should not be broken, even at the quantum level. Applying these principles one is able to extract universal rules for consistent quantum gravity theories, which get sharpened after the inclusion of so-called generalized symmetries. I will demonstrate the success and predictive power of such an approach in string theory and beyond.