When the swept tail of the North American continent became a land bridge to South America three million years ago, it changed the world. A once free-flowing ocean was now divided into the Atlantic and the Pacific. Its effect on ocean currents influenced the global climate, and the land bridge also became a biological connector as species that had developed in isolation began to travel between continents. This detailed physical map of Mexico and Central America includes three maps that trace the region's birth, before the final pieces of the geological puzzle completed the land bridge. Published in August 2007, this map was one half of a two-map set with a political map of Mexico and Central America.