Chicago raised street levels to make room for sewers, then lifted many existing buildings to meet them. An 1860 newspaper report describes 600 workers and 6,000 screw jacks lifting a Lake Street row 4 feet 8 inches in five days while business continued.

• ✓chicagology.com

Chicago lifted a row of buildings. The shops inside stayed open. The reason was under the street. The city was low and flat, making drainage a problem. To make room for sewers, Chicago raised the level of its streets. But now existing shop entrances could end up below the new sidewalk. Crews supported the structures on timbers and thousands of screw jacks. Turn a screw, and the support rises a little. Turn them together, and the building rises evenly. The row rose four feet eight inches in five days. New masonry supported the buildings at their higher level. An eighteen sixty newspaper reported that business continued while the work went on.