Global symmetries and gauge symmetries have played a crucial role in physics. The
idea of duality demonstrates that gauge symmetries can be emergent and might not
be fundamental. During the past decades it became clear that the circle of ideas
about emergent gauge symmetries and duality is central in different branches of
physics including Condensed Matter Physics, Quantum Field Theory, and Quantum
Gravity. We will review these developments, which highlight the unity of physics.
