Astronomers have known for a century that galaxies, immense clusters of stars and dust, populate the Universe far beyond our own Milky Way. The Hubble Space Telescope has revealed the full extent of this vastness through its deep field images, sprinkled with thousands of galaxies. Today, the James Webb Space Telescope is in turn revolutionising our understanding of their formation and evolution, revealing a surprising abundance of massive galaxies in the early Universe. Discover how Webb probes these celestial giants with its infrared vision, and how astronomers, including several in Canada, are helping to redefine our understanding of the structure of the Universe.