Getting started -- Location, location, location -- Floods, temperature, evolution, and it's about time -- How do they do that? -- Early on : the first modern ecosystems, middle Cretaceous through the early Eocene -- Transition : middle Eocene through the early Miocene -- Modernizing : middle Miocene through the Pliocene -- Latest touch : the great ice ages -- The bigger picture : implications of past environmental changes in the New World -- Pole to pole : a walk over the landscape, a walk through time.