It actually began with the Romans. They were the "white" race while others were either slaves or second tier citizens. Only a Roman had all rights. They invaded some of Africa, the middle east and Europe up to Britain. U.S. racism comes from Britain's Roman occupation.
There has always been slavery, but America made it inherited in perpetuity. America committed genocide against the people who were here first. Many of the survivors that genocide still live in concentration camp- like “reservations.”
Ours was not the first genocide and obviously won't be the last. Our slavery was no more disgusting than that of the Romans or other slave owning nations. What we need to know is that this may have begun with Rome and that something beautiful may have been forgotten in the process. Let's work on it.