Astrophysicists became deeply interested in black holes in the 1960s, but the idea of an event horizon was first intimated in a paper by Karl Schwarzschild published after Einstein introduced general relativity in 1915. Knowledge about black holes — objects that can't be directly seen — has grown tremendously in recent years. Part of this growth comes from researchers' ability to use detailed numerical models and powerful supercomputers to simulate the complex dynamics near a black hole — no trivial matter. The list of phenomena that must be included in an accurate simulation goes on and on: warped spacetime, gas pressure, ionizing radiation, magnetized plasma. To read further and to view a video, please visit https://www.tacc.utexas.edu/news/feature-stories/2014/let-there-be-light.