We've never seen them directly, but we know they lurk at the centers of galaxies, or wander the dust lanes and star fields of the Milky Way. Astronomers have discovered that black holes are the product of giant stars that die in a blaze of glory, and these powerhouses of energy have exerted a profound influence on the evolution of our universe. This curated series explores the breakthrough discoveries about these cosmic monsters that now shape our view of the universe.