Egypt not only didn't use slaves to build the pyramids (they were regular citizens and it was a kind of civic duty), but Egyptians weren't black. They were actually much more European looking than they are today as the area was colonized by the Sea Peoples, Greeks, and Romans. Nubians came up every now and then but didn't have much of an impact on their genetics. Then finally the Arabs came in and much ethnic cleansing was had.

Also, you can't point to a single country that didn't employ slavery in one way or another. Serfdom was only different from chattel slavery in that a person was tied to the land rather than a specific owner, however the person who owned the land basically owned the people. And unlike chattel slavery, serfs were regularly pressed into military service whenever the lord required.