ChicagoChicago's street raisingLifting a whole downtown with hand screws is a huge job. Was raising the buildings easier than digging them out, or was something already covering the old street?In the 1850s and 1860s central Chicago was raised to a new grade. Buildings were lifted on jackscrews, and in January 1858 a four-storey, 750-ton brick building at Randolph and Dearborn went up 6 ft 2 in.
Photo: Mark Hursh · CC BY-SA 3.0 · via Wikimedia Commons
Mud Flood · Seattle, United States
Seattle Underground
The open question
A whole storey of shops ended up below the street. Why build new streets a floor up instead of on the old ones?
On the record
After the 1889 fire, Pioneer Square's streets were raised from several feet to a full storey. The old sidewalks and shopfronts are still down there, lit by glass vault lights. The city condemned the Underground in 1907.
Sources
More from Mud Flood
ChicagoChicago's street raisingLifting a whole downtown with hand screws is a huge job. Was raising the buildings easier than digging them out, or was something already covering the old street?In the 1850s and 1860s central Chicago was raised to a new grade. Buildings were lifted on jackscrews, and in January 1858 a four-storey, 750-ton brick building at Randolph and Dearborn went up 6 ft 2 in.
ChicagoTremont House hotel liftWhy lift a big brick hotel rather than just fill in around it?In 1861 Ely, Smith and Pullman lifted the Tremont House hotel six feet to meet the new street grade.
SeattlePioneer Building, SeattleIf the old ground floor is underground, which floor was really the first one?Built in Pioneer Square after the 1889 fire; Bill Speidel's Underground Tour has run from it since 1965.
SacramentoOld Sacramento UndergroundFloods bring silt. How much of the raising was builders, and how much was mud already left by the water?After floods in the 1850s and 1860s, the worst in 1861–62, the city's streets were raised a level. The museum runs tours of the 'Old Sacramento Underground'.