Spanish settlements raked in much wealth by digging for gold in Mexico, and silver in Peru. The natives were completely dominated by the Spaniards, and were forced into slavery. They had to do gruelling work day and night in the gold and silver mines. Every bit of the gold and silver they unearthed was shipped back to Spain in regular convoys of galleons from the Americas. The monopoly of Spain in this field was greatly envied by other nations such as England, France and Holland.
Spain created two viceroyalties in the new world of America. The first in the Central America was New Spain, and the second, in South America, was Peru.
After conquering the Aztecs, Hernan Cortes started working on the construction of Mexico City. He destroyed the Aztec temples and buildings. Soon the place became the most important European city in the Americas. All these new settlements strengthened Spanish authority in South America. Thus, Spain became a mighty sea power.