  The tree-level scattering amplitudes of general relativity encode the full
non-linearity of the Einstein field equations. Yet remarkably compact
expressions for these amplitudes have been found which seem unrelated to a
perturbative expansion of the Einstein-Hilbert action. This suggests an
entirely different description of GR which makes this on-shell simplicity
manifest. Taking our cue from the tree-level amplitudes, we discuss how such a
description can be found. The result is a formulation of GR in terms of a
solvable two-dimensional CFT, with the Einstein equations emerging as quantum
consistency conditions.
