Today is Memorial Day in the United States. Memorial Day is a modification of an earlier day of commemoration, Decoration Day, which was in turn created to honor those Union soldiers who died in the American Civil War.
To present some context, consider that more than 600,000 American men at arms died in the Civil War. The population of the U.S. in 1865 was around 35 million. This means that the Civil War claimed about 1.7% of the population, or 1 out of every 59 people. (1 out of every 30 men.)