  We make a proposal for the string dual to the simplest large $N$ theory, the
Gaussian matrix integral in the 'tHooft limit, and how this dual description
emerges from double line graphs. This is a specific realisation of the general
approach to gauge-string duality which associates worldsheet riemann surfaces
to the Feynman-'tHooft diagrams of a large N gauge theory. We show that a
particular version (proposed by Razamat) of this connection, involving integer
Strebel differentials, naturally explains the combinatorics of Gaussian matrix
correlators. We find that the correlators can be explicitly realised as a sum
over a special class of holomorphic maps (Belyi maps) from the worldsheet to a
{\it target space} ${\mathbb P}^1$. We are led to identify this target space
with the riemann surface associated with the (eigenvalues of the) matrix model.
In the process, an AdS/CFT like dictionary, for arbitrary correlators of single
trace operators, also emerges in which the holomorphic maps play the role of
stringy Witten diagrams. Finally, we provide some evidence that the above
string dual is the conventional A-model topological string theory on ${\mathbb
P}^1$.
