The Nazis established a massive, systemic and vicious program for the complete annihilation of any "enemy" of the aryan race, and by "enemy" we are talking about innocent jews, Romani and many more (although, the complete annihilation of the jewish people was it's main target). You may know this as the "Final Solution". I'm not aware of any event in modern human history that resembles the scale, the intent, the execution level and the pure evil that makes the final solution program.
This does not mean that other atrocities done by any other group of people (including the "allies") are not horrific and should not be condemned or remembered. But, the final solution should always be remembered as an extreme, unique and singular event in modern human history.
This does not mean that other atrocities done by any other group of people (including the "allies") are not horrific and should not be condemned or remembered. But, the final solution should always be remembered as an extreme, unique and singular event in modern human history.