A continent that runs from the permanent ice of Ellesmere Island to the rainforest of Panama, and the course follows it in that order: first the land, then the countries standing on it, then the people. You start with the shape of the place — the Rocky Mountains and the ancient, worn Appalachians, the Canadian Shield that four ice ages scraped bare, the Great Plains, the Mississippi that drains about 40 percent of the contiguous United States, and the five Great Lakes that hold a fifth of the planet's surface fresh water. From that you get the climates, because relief is what makes them: why the Pacific coast is wet and the land just east of the mountains is dry, why hurricanes arrive from the southeast and tornadoes form in the middle, and why the Arctic north and tropical south belong to the same landmass. Then the three big countries, one at a time: the United States region by region and how it became the economy it is; Canada, the second-largest country on Earth, whose people live almost entirely within 200 kilometres of one border; Mexico and the seven countries of Central America, from the volcanic spine to the isthmus that split an ocean in two. The last track is the part atlases leave out — the nations who were here first and are still here, the Nahua, Maya, Cree, Navajo, Inuit and hundreds more, and the migrations that made this the most linguistically mixed continent on the planet, ending in the cities where most North Americans now actually live.