In the wetter north, there are thickly forested slopes and snowy peaks climbing to over 6000m. Much of the dry south is scorching desert with salt flats and deep canyons. Beyond the Rockies, a vast plain stretches east for thousands of kilo-metres to the Appalachian Mountains and north to the old hard rocks of the Canadian Shield. In the drier west of this plain is the grassland of the Great Plains, where millions of cattle and sheep graze on ranches. In the heart lie the flat prairies, where wheat grows in fields stretching as far as the eye can see.
Further south is the cotton belt, either side of the great Mississippi river.
And in the middle of the continent are the five Great Lakes - Superior, Michigan, Huron, Erie and Ontario, among the largest lakes in the world. East of the Appalachians is the Atlantic coastal plain, where Europeans first settled. This area is still very densely populated and includes the huge city of New York, with a population of over 17 million. Houston, Texas is one of the fastest-growing cities in the USA, and home to the US space agency NASA's Johnson Space Center. The Grand Canyon in Arizona is 450km long, up to 20km wide and 1615m deep.