  We argue that the holographic formula relating entanglement entropy and the
area of a minimal surface is the key to define the area of surfaces in the
(emergent) spacetime from the dual theory on the boundary. So we promote the
entropy/area relation to operators to define the "area" observable in a
holographic formulation of quantum gravity, then we find a suitable geometric
representation for the states, and show that the Ryu-Takayanagi proposal is
recovered in the approximation of semi-classical gravity. Finally, we discuss
this picture in the example of a AdS-Black hole.
