Abstract: We have no evidence that general relativity is wrong; every precision test is a resounding confirmation of this elegant and powerful mathematical model. Trouble is: the greatest cosmological problems of our time (likely require) us to abandon general relativity. About 95% of the Universe remains a mystery whose solution evades our abilities. I will talk about how there may still be places in general relativity that have, until now, gone unexplored. Numerical simulations are a powerful tool that can model the complex non-linear issues of general relativity on cosmological scales. I will present progress that we have made toward modeling the late Universe in its full splendor and outline where there’s hope that we can start to tackle these great questions.