Where did Europeans in the sixteenth century find a cheap labor source for work in the new world?

In Africa, the Europeans found cheap labor source for work in the new world.

Explanation:

As the native European population was dying because of diseases, they wanted to rely on the Africans as a cheap labour source. This is because the Africans are more resistant to European diseases. As they can work very hard in hot climates, they brought over ship. Poor Africans died due to starvation and improper medical care. Due to the African slaves, European countries became wealthy in plantations and mines. Due to this reason, diverse population and different culture is existing in Europe.