The Planck space telescope has made the first conclusive detection of a bridge of hot gas connecting a pair of galaxy clusters across 10 million light-years of intergalactic space. In the early Universe, filaments of gaseous matter pervaded the cosmos in a giant web, with clusters eventually forming in the densest nodes. However, much of this tenuous, filamentary gas remains undetected. The presence of hot gas between the clusters was first hinted at in X-ray data from ESA's XMM-Newton and the new Planck data confirms the observation.