in 1919, a black boy paid with his life and set off a riot in Chicago for inadvertently breaching this pillar of caste. Seventeen-year-old Eugene Williams was swimming in Lake Michigan, at a public beach on the city’s South Side, and happened to wade past the imaginary line that separated the races. He unknowingly passed into the white water, which flowed into and looked no different from the black water. He was stoned and drowned to death for doing so. The tensions over the breaching of boundaries that summer incited the dominant caste and set off one of the worst race riots in U.S. history.