How did half a mill die?

The phrase "half a mill die" seems unclear; however, if you're referring to a historical event or metaphor, please clarify. If you're asking how half a million people died in a specific context, various events such as wars, pandemics, or natural disasters could account for such a loss of life. For instance, the COVID-19 pandemic resulted in millions of deaths worldwide due to the virus and its complications. Please provide more context for a more accurate response.