In the early 1900s white and black Chicagoans often lived side by side. But as blacks began flowing into the city in larger numbers during World War I, whites set about protecting their neighborhoods from racial integration. Often they relied on informal means, such as dynamite. But they also used the law. By the late 1920s almost all white neighborhoods were subject to "restrictive covenants" that banned black residents, though house servants, janitors, and chauffeurs were charitably allowed to live in their employers' basements or garages. In 1937 Carl Hansberry and his family moved into a brick three-flat in west Woodlawn. The Hansberrys were black, the neighborhood white. This set off a legal battle that Hansberry won in the U.S. Supreme Court in 1940. But he won on procedural grounds; not until 1948, in a case involving restrictive covenants in Saint Louis and Detroit, did the high court find such covenants unconstitutional. Bricks and bottles were hurled at the Hansberry home after the family's arrival, and the children were spat on, but the Hansberrys stayed and the neighborhood soon changed to black. The youngest of the four children, Lorraine, went on to write the hit Broadway play A Raisin in the Sun, about a black family considering a move to a white neighborhood. The brick three-flat was designated a Chicago landmark in 2010.