Mexico is a vast country dominated by a great chain of mountains, the Sierra Madre; there is a wide variety of life, from black bears and orchid bees to resplendent quetzals and millions of monarch butterflies.

The ancient temples of the Maya still tower over the forests of the Yucatan, where jaguars, monkeys and vibrant tropical birds now make their home. It is a forest full of secrets, with a vast watery underworld that is still being explored and which holds the key to how animals and people survive the dry season.

Northern Mexico is the country's driest region, dominated by two great deserts - the Sonoran and Chihuahuan. And as you travel west, the conditions get hotter, drier and more challenging. In this film, we unravel the forces that have created this arid world and discover that for the animals who live here, from prairie dog and pygmy owls to rare aplomado falcons, overcoming these conditions can bring rich rewards.