How the landscapes of America's three great mountain ranges - the Appalachians, the Rockies and the Sierra Nevada - challenged the westward push of the early pioneers.
Ray Mears finds out how 500,000 square miles of flat, treeless grassland was the setting for Wild West stories of Indians, wagon trains, homesteaders and cattle drives.
Ray Mears looks at how the landscapes of America's five great deserts, from the Great Basin desert to Arizona's Sonoran desert, challenged the westward push of the pioneers.