Certain Party or Parties Unknown (CPPU) is a temporary multi-media public art exhibition furthering community dialogue about racial justice in Montgomery County, Maryland. The Arts and Humanities Council of Montgomery County (AHCMC), as a member of Montgomery County’s Remembrance and Reconciliation Commission, commissioned six regional artists—Curtis Woody, Nikki Brooks, Tim Davis, Alix Lambert, Liz Miller and LaShell Rivers—to project temporary public art installations onto eight county sites in downtown Rockville on November 5 and 6, 2021. The exhibition is focused on three African American men who fell victim to racial terror lynchings in Montgomery County in the 1880s: Mr. John Diggs-Dorsey, Mr. George Peck, and Mr. Sidney Randolph.