It is difficult to accurately calculate the total number of fatalities during the Civil War, but for many years the standard figure was 620,000 across both armies. Some newer research, however, has suggested that the death toll was much higher – at around the 750,000 mark. Either way, that's more Americans dead than in World War I (116,000), World War II (420,000) and the Vietnam War (58,000) combined.
Yet by far the biggest killer was not fighting, but disease. Around two-thirds of the total deaths were caused by illnesses like dysentery, pneumonia, typhoid and malaria.