I will review the results of the SH0ES program (PI: A. Riess), which has recently obtained an absolute calibration of the luminosity of type Ia SNe via Cepheid variables and determined the value
of H_0 with a total uncertainty of 3%. This provides important additional constraints on several cosmological parameters, such as the equation of state of dark energy and the number of neutrino
species. I will also discuss future steps that may enable a determination of H_0 to 1%.