The Spanish and Portuguese conquest of America could be characterized as fortuitous because of the way in which it was discovered. Christopher Columbus happened upon the Americas by pure chance while searching for a quicker route to India and the other riches of the east. He established Hispaniola as America's first European colony. This colony eventually led to the introduction of new plants, animals and diseases that have changed the lives of the people of the Americas. This is referred to as the "Columbian Exchange"; it is not regarded as positive change by the indigenous people of the Americas. Diseases like the common cold, as referred to in the film Aguirre, were deadly to natives who had no natural immunity to them. Aside from new disease, the Spanish began to exploit the resources, both natural and human, in the Americas. Later, the conquistadors entered and began their expeditions in search of wealth. To the Spanish, they were conquering the heathens in the name of Catholicism, but to the natives, these men were killing their families, taking their lands, and destroying their earth. The conquests shaped the emerging system of land ownership. The conquistadors fought seeking riches and land grants (encomiendas). This led to the development of the hacienda system, which was the active system until the 20th century. In America today, there are more mixed races than anywhere on the planet. Castas, people of mixed blood, became the largest social class in the 18th century. Racial mixing is one of the defining characteristics of the Americas today. The conquest of America, although progressive, should not be considered a positive movement. From its beginning after discovery, to its end in 1825, the conquests led to the unnecessary murder and enslavement of millions of natives and the poverty of many places in the Americas today. Although the people were free to progress as the pleased after the revolution, they were poorly prepared to establish any type of stable government.