tl;dr: The DESI Legacy Imaging Surveys team has released a 5.6-trillion-pixel 2D map of the universe, covering 75% of the sky and containing nearly 4 billion stars and galaxies, built from 263,407 telescope exposures processed on the Perlmutter supercomputer. The publicly available map serves as the targeting foundation for the Dark Energy Spectroscopic Instrument (DESI), which recently completed its 5-year survey and produced early hints that dark energy may be weakening over time. It will also serve as a reference dataset for upcoming observatories like Vera C. Rubin and Nancy Grace Roman, and for training AI analysis tools.