Yesterday, the 150th anniversary of the bloodiest day in US history - Antietam.
Twenty-three thousand men were killed, wounded or went missing that day. Never before, or since, have so many Americans fallen in battle in a single day.
One of the not-so-well-known facts is how many of those who fought that day were foreign-born. Overall, immigrants made up 25 percent of the Union army in the Civil War: thats a far greater proportion than immigrants made in the general population.
According to Patrick Young, a history blogger and immigration advocate, many joined because of their opposition to slavery.
Others, Young says, were always writing about how the United States was the only hope in the world for freedom and democracy what they called republicanism. Princes and Kings would rejoice, Young quotes foreign born soldiers as saying, if the United States were split apart.
The US suffered 3,500 casualties in the Pearl Harbor attack; 6,600 at D-Day by comparison. The only thing close to comparable was Gettysburg where there were 55,000 casualties in the 3-day battle.