In this week’s episode of “Who Do You Think You Are?,” airing at 9 p.m. Sunday on TLC, Julie Bowen (“Modern Family”) travels to Chicago to check out some key aspects of her heritage. In the episode, the actress visits the Art Institute of Chicago and the Pritzker Military Library to learn about an ancestor, who had moved to Chicago to become an artist.

Bowen also discovers he was a prominent member of the American Protective League during World War I. The league was founded in Chicago in 1917 to help law enforcement agencies identify suspected German sympathizers and focus on the activities of left-wing labor union members, anarchists and anti-war activists.