 All indications from string cosmology point to the fact that the universe existed before the big bang. In particular, string theory claims that if we apply fundamental symmetry transformations to cosmological models of the recent universe, then we get a copy of the universe (with important quantities inverted) that might be called the “pre-big-bang universe.” In this scenario, the absolute big bang disappears and is replaced by a saddle point in the dynamical evolution of spacetime curvature: before this point, curvature is increasing, and after this point, it is decreasing.