The Millennium Simulation—a renowned supercomputer model created in 2005 by Volker Springel and the Virgo Consortium at the Max Planck Institute for Astrophysics—illustrates the large-scale gravitational evolution of the cosmos. Tracking the evolution of cold dark matter from redshift 20 down to a redshift of 0 (the present day), a timelapse video of a 500-Mly patch shows the spectacular “cosmic web” emerging. Over time, gravity pulls the dark matter into sweeping filaments that intersect at ultra-dense clumps, or nodes. Even though the simulation tracks invisible dark matter, it effectively maps the universe’s visible galaxy distribution. This is because normal gas flows into the gravitational wells of these dense dark-matter halos, where it condenses to form the visible galaxies we see today. Visually, this interconnected web of matter bears a striking resemblance to the neural structure of a human brain, or to satellite images of brilliantly lit cities connected by sprawling highways at night.