I will describe two frontiers that will likely provide new testing grounds for the theory of gravity. The first frontier holds the potential for measuring the gravitational growth of density fluctuations (in the weak field regime) throughout most of the observable volume of the Universe by mapping the distribution of cosmic hydrogen before, during, and after the epoch of reionization. The second frontier includes new tests of the theory of gravity in the strong field regime, based on direct imaging of the silhouette of nearby black holes (SgrA* and M87) as well as observing electromagnetic signatures from the coalescence of black hole binaries
at cosmological distances.