If you grew up in the United States, you most likely learned about the massive military battles and large-scale political fights that shaped the course of the American Civil War.

Major moments in the history of the country carried out by names like Robert E. Lee, Ulysses S. Grant to Abraham Lincoln.

The Civil War fought between the North and South from April of 1861 to April of 1865,

remains the deadliest military conflict in the history of the United States.

The number of those who died fighting in the Civil War, estimated to be at least 620,000,

is more than the number of Americans who died fighting in the War of 1812,

the Revolutionary War, World War I, and World War II combined.

But amidst the well-told stories of the Civil War, there is one that is much lesser known.

And it's this hidden moment, a chance discovery really, which set off the bloodiest day in American military history,

and changed the entire outcome of the war and the future of the United States.

Sometimes it's better to be lucky than good.

On today's episode, Robert E. Lee's Lost Orders.

This is a twist of history.

It's early morning on September 6, 1862, on the banks of the Potomac River outside the town of Frederick, Maryland.

A young man walks down a path toward the riverbank enjoying a pleasant summer day.

But as he gets closer, he hears something in the distance, and he stops.

It sounds like it's coming from the river and it's bizarre, like hundreds of voices singing

out in unison.

The young man runs down the path and the sound gets louder.

As he approaches the riverbank, he shields his eyes from the sun and what he sees is even

stranger than the sound.

For a second, he can't wrap his mind around it, because in the shallows of the river, it looks like an army of dead men are waiting towards him, and they're singing.

...