Why did Europeans begin to take slaves from Africa?

Europeans began to take slaves from Africa primarily due to the demand for labor in their colonies, particularly in the Americas. The growth of cash crops like sugar, tobacco, and cotton required a substantial workforce, and indigenous populations were often decimated by disease and conflict. African slaves were seen as a more sustainable labor source, leading to the establishment of the transatlantic slave trade. This trade became a significant part of European economic expansion and colonialism during the 16th to 19th centuries.