When Rosa Parks refused to give up her seat, the Rev. Bob Graetz drove her to work the next… When Rosa Parks refused to give up her seat, the Rev. Bob Graetz drove her to work the next day.

Graetz, who is white, took over an all-black congregation in Montgomery, Ala., late in 1955. Little did he know that one month later he would be an integral part of the most famous bus boycott in history.

On Tuesday night, he came to Carnegie Mellon University