The European explorations completely changed the entire "New World." For example, the Aztec capital, Mexico, was the center of arguably one of the most powerful and advanced civilizations in the world during the explorations. It was a city of over 1 million people in population, something generally unheard of by Europeans during the 15th and 16th century. After Cortez was driven out of the capital by the warriors within it, he left behind a small pox epidemic that, some historians have estimated, killed up to 90% of their population. Cortez later returned and destroyed what was left of the city.
Similar events occured elsewhere throughout the Americas, in all killing more than half the native populations through disease and war. Most of those who survived became slaves, or became second class citizens in their own lands, subordinate to the European population who began emigrating.
