  Translating the dynamics of the Henon--Heiles hamiltonian as a geodesic flow
on a Finsler manifold, we obtain a local and synthetic Geometric Indicator of
Chaos (GIC) for two degrees of freedom continuous dynamical systems. It
represents a link between local quantities and asymptotic behaviour of orbits
giving a strikingly evident, one-to-one, correspondence between geometry and
instability.
