Geography is central to understanding Mexico's uneven development. Historians and other scholars have also known that geography has played an important role in constraining Mexico's development. Mexican ports such as Veracruz, Tampico, Manzanillo, and Lazaro Cardenas are nationally and regionally important but globally insignificant. United States in particular has been also greatly favored by location, benign climates, and many other features of the nation's land mass that in combination with one another have provided unequalled favorable conditions for bounteous economic growth and development. Mexico's unique shape, topography, and climatic features long ago produced a great concentration of population and economic activity in the interior territories of the country, rather than in the coastal areas. Nature is just as challenging in Mexico's western littoral as it is on the Gulf and Caribbean coasts. Acapulco was Mexico's most important port on the Pacific coast from the 1500s to the dawn of the twentieth century.