Final answer:
The Discovery of the New World in 1492 caused Europeans to turn to Africa for slave labor, due to the depletion of Native populations and the need for labor in their American colonies. This marked the start of the Atlantic Slave Trade.
Step-by-step explanation:
The event that led Europeans to look toward Africa as a primary source of slaves was the Discovery of the New World, or the Americas, in 1492. Prior to the Discovery, Europeans employed Native populations for labor, but the spread of diseases and brutal working conditions depleted these populations. As a result, the growing European colonies in the Americas needed a new source of labor to support their economies, especially in sugar cane, tobacco, and later cotton plantations. Africans were then targeted due to the established trade networks and their supposed 'resistance' to diseases. This process marked the beginning of the Atlantic Slave Trade.
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