Abstract: The Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC) are creating the most ideal fluid ever observed, the quark-gluon plasma, by smashing together heavy nuclei at relativistic energies. This phase of matter existed only a few microseconds after the big bang. I will review the state of the art of lattice QCD simulations at finite temperature and density, which reveal the properties of this phase of matter and the temperature and density at which it is created. I will then discuss phenomenological methods to extend these results to higher densities and connect them to the Second Beam Energy Scan program at RHIC.