The fact that approximately 6 million Jews were murdered by the Nazi regime during World War II is well-known to educated Americans. Much less well-known are the facts of Roma persecution during World War II. Historians estimate that between 250,000 and 500,000 Romani people were systematically murdered by the German regime, out of a prewar European population of perhaps 1 million.

https://slate.com/news-and-politics/2023/03/romani-jewish-holocaust-history-compensation-victims.html