Sandhogs (tunnel workers) posing on the cutting edge of the shield used in the construction of a subway tunnel under the East River.

The miners who work on underground or underwater tunnels trace their union back to the first strike against dangerous conditions during the building of the Brooklyn Bridge, on May 8, 1872.

Image from the Civil Service Technical Guild Collection, Robert F. Wagner Labor Archives, New York University.

See this image in the Ordinary People, Extraordinary Lives exhibit.