The “underground” is generally understood as a place beneath the surface of the earth. But in twentieth-century visual arts and literature, the term had a wide diversity of meanings. Suffused with a romantic and dreamlike spirit, the underground—cellars, catacombs, and sewers—represents a dark and inverted mirror of what happens on the streets. It is the unconscious of cities.
In the 1930s and ’40s in New York and other urban centers, photographers took to the subway to document commuters. With the Second World War underway in Europe, subway stations and tunnels became shelters to escape bombardments. In France la résistance was formed of underground secret networks fighting against Nazi occupation. After the war, in 1952, the American writer Ralph Ellison published his landmark novel Invisible Man, whose narrator lives in an underground room wired with hundreds of electric lightbulbs—a metaphor for the social invisibility experienced by Black people in the United States.