The cosmic web—the distribution of matter on the largest scales in the universe—has usually been defined through the distribution of galaxies. Now, a new study by a team of astronomers from France, Israel and Hawaii demonstrates a novel approach. Instead of using galaxy positions, they mapped the motions of thousands of galaxies. Because galaxies are pulled toward gravitational attractors and move away from empty regions, these motions allowed the team to locate the denser matter in clusters and filaments and the absence of matter in regions called voids.