Understanding gravity on cosmological scales

In this presentation I will describe classical methods to test gravity on cosmological scales, particularly from the use of the anisotropic clustering of galaxies as observed by large redshift surveys. I will show its importance to probe cosmic acceleration and present the recent eBOSS galaxy survey results. In additional to galaxy clustering, weak gravitational lensing can be used efficiently and combined to provide further insights. This combination has a strong potential and should allow the performance of genuine tests of General Relativity. I will discuss such tests and the sensitivity to second-order relativistic effects that may be become observable in future large surveys. Finally I will give some prospects on the achievements of next-generation experiments such as Euclid or DESI, particularly on our ability to solve the problem of late-time cosmic acceleration.