European exploration had a lot of side effects. When the Old World and the New World began to interact, people, wealth, food, animals, and disease began to flow in both directions. In the New World, countless millions were killed by smallpox, measles, and other Old World diseases. Old World animals changed life in the New World irrevocably, and the extraction of wealth and resources from the Americas ultimately contributed to the development of the Atlantic Slave Trade. So, it was an exchange with a lot of downside, especially for non-Europeans.