When a superconductor is exposed to a magnetic field, a current on its surface appears which creates a counter field that cancels the magnetic field inside the superconductor. This phenomenon, known as “Meissner-Ochsenfeld effect” after its discoverers, was first observed in 1933. Physicists have now succeeded in realizing an analogue of the Meissner effect by measuring edge currents in a ladder-like crystal of light.