Before Holocaust: There was Herero & Nami Massacre, Namibia by the Brute Germans Whites:

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The Herero and Nama Genocide (1904–1908) was the first genocide of the 20th century, where Imperial German colonial forces slaughtered tens of thousands of indigenous Herero and Nama people in modern-day Namibia. It set a grim historical precedent and is considered by many historians to be a precursor to the Holocaust