This bell is on the Bay Bridge Tower. Take a look at that thing, it's almost as big as that door. I'm sure it's a very outdated collision avoidance bell (CAB) that's been replaced by a horn or some other electronic device. But it's just too big to move and what the heck else are you going to do with it?
I took the shot as we were going by for two reasons: 1) it's really cool and 2) do you think it rang when the Cosco Busan hit it*?
* it was a different tower but I bet it has a matching bell.