In 1930, Indiana Bell, a subsidiary of AT&T, needed a larger building for their headquarter. The problem? The old building needed to stay in operations at all times, providing an essential service to the city. Instead of tearing it down or simply moving to a new building, they decided to move it to a different part of the lot and build on the existing location. Just that.

The massive undertaking began on October 1930. Over the next four weeks, the massive steel and brick building was shifted inch by inch 16 meters south, rotated 90 degrees, and then shifted again by 30 meters west. The work was done with such precision that the building continued to operate during the entire duration of the move. All utility cables and pipes serving the building, including thousand of telephone cables, electric cables, gas pipes, sewer and water pipes had to be lengthened and made flexible to provide continuous service during the move. A movable wooden sidewalk allowed employees and the public to enter and leave the building at any time while the move was in progress. The company did not lose a single day of work nor interrupt their service during the entire period. Incredibly most of the power needed to move the building was provided by hand-operated jacks while a steam engine also some support. Each time the jacks were pumped, the house moved 3/8th of an inch.

(via the excellent The Prepared newsletter)

Update: Using the sequence of photos of the move, Statistics_Data_Facts made some animated GIFs of the building’s pivot.