Photos: Tobias Kleinlercher / Wikipedia · CC BY-SA 3.0 (1, 2, 3) · Fietsbel · CC BY-SA 3.0 · Han Zheng · CC BY-SA 2.0
A brick car barn on Nob Hill where four winding machines drive the cable loops, with a gallery above them and a viewing room below street level.
Why it's unique
This is the system's working powerhouse rather than a display about it. The machines turning below the gallery are hauling the cable under the streets around you, so every car on the network depends on the room you are standing in.
It follows from the cable car system being singular that this building is too, though no source puts it in quite those terms, so confidence sits below certainty.
Before you go
Do both levels. The top-floor gallery looks down on the four winding machines, and the sheave room below has a glass wall that lets you look under the street at the pulleys turning the cable loops.
Friday to Sunday it stays open an hour later than midweek. It is closed Mondays.
