Our joint analytical and computational study has recently appeared in Physical Review Letters. This work provides microscopic insight in the dynamical fluctuations observed in glass-forming liquids. The phenomenon, which was first identified in the 1990s, has been speculated by some to play an important role in glass formation, yet a first-principle explanation for it had thus far remained elusive. The close collaboration between star physicists Dr. Yi Hu (Duke) and Dr. Giampaolo Folena (ENS-Paris) has finally cracked that puzzle!