First was the enslavement for their labor and resulting early deaths and murders of tens of millions of Africans.
The second was the slaughter of millions of indigenous peoples and the simultaneous and subsequent land robbing by European new comers. These peoples had inhabited and still do inhabit the U.S. continent long before any Europeans arrived.
Often the survivors of these massacres tried to blend into society and hide their ethnic roots. Often the children were abducted from their family and taken to far away institutions and