  This is a review of some recent works which demonstrate how the classical
equations of gravity in AdS themselves hold the key to understanding their
holographic origin in the form of a strongly coupled large $N$ QFT whose
algebra of local operators can be generated by a few (single-trace) elements. I
discuss how this can be realised by reformulating Einstein's equations in AdS
in the form of a non-perturbative RG flow that further leads to a new approach
towards constructing strongly interacting QFTs. In particular, the RG flow can
self-determine the UV data that are otherwise obtained by solving classical
gravity equations and demanding that the solutions do not have naked
singularities. For a concrete demonstration, I focus on the hydrodynamic limit
in which case this RG flow connects the AdS/CFT correspondence with the
membrane paradigm, and also reproduces the known values of the dual QFT
transport coefficients.
