Cornerstone is a civil rights mural that anchors the corner of the new Rockville Town Square near Washington DC. This site-specific artwork faces North Washington Street, a centuries-old roadway with Native American, Colonial, Revolutionary, and Civil War history. Three banners with historical text include the "X" marks of twenty illiterate freedmen on a pledge to pay for Rockville's first black school in 1867. The artwork highlights a cluster of African American heritage sites from the 18th, 19th and 20th centuries, now largely obscured by development.