An article published in the journal “Science” reports the discovery of massive gas filaments between the galaxies of a protocluster cataloged as SSA22 about 12 billion light years from Earth. A team of researchers coordinated by the RIKEN Cluster for Pioneering Research used the MUSE spectrograph mounted on the VLT in Chile and the Suprime-Cam on the Subaru telescope to map those filaments, which extend over more than 3 million light years. Follow-up observations that provided further details were conducted with the ALMA radio telescope and the Keck telescope. The filament gas can feed star formation and the growth of supermassive black holes in the protocluster. The observation of those processes can provide new information on the evolution of galaxies.