6. As a result of the Spanish Conquest of the Aztec Empire, an estimated 24,000,000 people lost their lives
The Spanish-Aztec War of 1519-1521 was the first conquest by the Spanish Empire of a major pre-Columbian American civilization, setting in motion the European colonization of the Americas. Arriving in Mexico in 1517, two years later an expedition led by Hernán Cortés embarked with the goal of subjugating the native populations. Marching on the city of Cholula, the second largest in Mesoamerica and the center of the Aztec religion, Cortés was welcomed as a guest. Ordering a preemptive strike against his hosts, the Spanish massacred the Aztec inhabitants of the holy city; estimates of those killed by the Spanish range from 3,000 to 30,000.
Marching on the island capital of Tenochtitlan, one of the largest cities in the world with an estimated population of 250,000-300,000 people, the Aztec Emperor, Moctezuma II, welcomed the Spanish to his city. Forced to flee after some of his men attacked and killed much of the Aztec nobility in the “Massacre in the Great Temple”, Cortés would return in 1521 to complete his conquest. Establishing the new capital of Mexico City on the ruins of Tenochtitlan, in 1522 Holy Roman Emperor Charles V proclaimed Cortés captain-general of New Spain as a reward for his services and genocide.