Why does the color change on the outside of the monument?
When the monument was under construction the project ran out of money. It sat uncompleted for 27 years until they could restart the project the stone above the line wasn't exposed to 27 years of pollution and wind driving dirt/dust.
Did You Know?
Private Johnny Cook, a bugler with Battery B, 4th U.S., was awarded the Medal of Honor for his actions at Antietam when he was only 15 years old.