Abstract. The new generation of cosmological surveys like DESI, J-PAS and Euclid will measure the effect of dark energy on the expansion history of the universe. They will obtain optical and NIR spectra for tens of millions of galaxies and quasars, constructing a 3-D map spanning the nearby universe to 10 billion light-years, and will provide an accurate determination of the distance-redshift relation. I will review the latest distance scale measurements using Baryon Acoustic Oscillations, and discuss the hopes and prospects for discovering new physics in the Euclid era.