A supersolid is a bizarre quantum state that is rigid like a solid, yet can flow like a zero-viscosity liquid (a superfluid). After many years of theoretical arguments as to whether this sort of material could even exist, two groups have now reported making it. Jung-Ru Li and colleagues of MIT started with sodium atoms configured in a Bose–Einstein condensate such that lasers could nudge them to line up spatially as if they were in a crystal. Julian Léonard and colleagues of ETH Zürich also began with an atomic superfluid, but placed it in an optical cavity and excited the atoms with a laser causing them to emit photons into the cavity and thus create a standing wave that guides the atoms into orderly positions. The two studies open up a new field of investigation in which many interesting questions, even including whether or not supersolids are in thermodynamic equilibrium, remain open.