Americas

<p>The Americas stretch from the Arctic Circle in Canada to the southern tip of Chile. This geographically, culturally and politically diverse region is home to the United States, a nation whose geography helped it become the foremost economic and military power in the world &mdash; an ascendance aided in part by bringing Mexico and Canada into its sphere of influence. Farther south, the nations of South America are like islands, separated by vast spaces of impenetrable mountains, rivers and jungles. Try though these countries may to integrate more closely, deeper ties such as those that characterize North America will prove elusive.</p>