I grew up with Pacific Bell. Since then the phone company has been known as SBC and AT&T. Here is a Wikipedia article about PacBell, and AT&T's own history page. I'll admit this is one of my nerdier projects.
First, what I think are really pretty manhole covers:
Next, in chronological order of their existence (I think) are telephone vault covers.
A hybrid "Bell System" and Pacific Telephone:
The more recent and scarce SBC:
And finally, the most recent, AT&T: