CHICAGO (CBS) — It hasn’t generally been taught in Chicago schools, but the city is home to a memorial to Confederate soldiers, at a cemetery in the Greater Grand Crossing neighborhood.

During the Civil War, the Union Army first used Camp Douglas – located in what now is the Bronzeville neighborhood – as a training camp for volunteer regiments, but it later became one of the largest prisoner of war camps for Confederate soldiers.

According to the National Park Service, more than 26,000 Confederate soldiers spent time at the prison camp, near what is now the intersection of 31st Street and Cottage Grove Avenue.

“Somewhere between 5 and 6 thousand died while imprisoned here. They were initially buried at the city cemetery in the southern end of Lincoln Park,” said David Keller, managing director of the Camp Douglas Restoration Foundation.

When that cemetery was closed due to constant flooding, the remains of more than 4,000 Confederate soldiers were moved to a mass grave at Oak Woods Cemetery, at 67th Street and Cottage Grove Avenue.

A 30-foot granite memorial to those soldiers still stands at Oak Woods Cemetery at Confederate Mound. The granite column is topped with a bronze statue of a Confederate soldier, and features bronze plaques inscribed with thousands of names. The site also features four Civil War cannons, 12 headstones marking graves of Union prison guards, and a large cannonball pyramid.