  We review recent results on the potential energy landscape (PES) of model
liquids. The role of saddle-points in the PES in connecting dynamics to statics
is investigated, confirming that a change between minima-dominated and
saddle-dominated regions of the PES explored in equilibrium happens around the
Mode Coupling Temperature. The structure of the low-energy saddles in the
basins is found to be simple and hierarchically organized; the presence of
saddles nearby in energy to the local minima indicates that, at non-cryogenic
temperatures, entropic bottlenecks limit the dynamics.
