There are certain moments in US history when Confederate monuments go up

To hear their defenders say it, Confederate memorials aren't symbols of hate; they are meant to honor a heritage.

But, as this chart above from the Southern Poverty Law Center shows, whenever the country appeared to have made some racial progress, cities and states -- mostly in the South -- responded by erecting such monuments. 

There are two distinct spikes: one around the turn of the 20th century, and one during the height of the civil rights movement.