Mystery of San Francisco's sinking tower

Supposedly the west corner of the Millennium Tower (corner of Mission and Fremont in SF) has sunk 20 inches since the building was new. No question the building has tilted – if you hang a plumb bob from the west corner of the roof, the bob will be 28 inches west of the bottom corner of the building. The puzzle is, why can’t we see the sunken bottom?

2009 view

2025 view

Has the building sunk 20 inches and pulled the sidewalk down with it? And the street? Both sides of the street?

(I checked the latter – as I recall the SE curb of Mission was about 5 inches lower than the NW curb, in 2016. The other thing I checked was that big blue-top fire hydrant on the Mission St side of the building. In 2016 it was 6-1/2 inches lower than it was circa 1998, relative to hydrants a block or two away.)

More reading https://media.api.sf.gov/documents/10.24.2025_Monitoring_Report_140.pdf

I don’t know, but having dealt with the developers of the project, I hope the whole thing fails and brings them down with it.

Yes, the surrounding area is sinking too so there’s no one point where the sinking is dramatically visible. The only evidence visible to the naked eye would be cracked sidewalks and curbs.