Dan Egan at the NYT:
So, Chicago’s leaders got creative. Instead of putting sewers under the streets, they put sewers on top of the streets, then built new roads atop the old ones. They effectively hoisted the city out of the swamp.
Buildings in downtown were raised by as much as eight feet, an enterprise that required placing immense beams and jackscrews beneath their foundations. Then, a conductor would direct hundreds of laborers in the precisely choreographed turns of the screws to lift the structures out of the muck.
“The superintendent takes his stand,” the Chicago Tribune wrote at the time, and with a “shrill whistle” directs the crew to begin.