Also known as Route 123, San Pablo Avenue is a four lane road that runs along the east bay (San Francisco bay, people) going north-south. For those that were asleep in geography, San Francisco is at the entrance to a bay, in the north-middle coast of California, which is in turn in the United States.
There are various accounts of the history of the road, at one point it was supposed to have been part of Route 1, which went coast to coast, and was also part of US 40, which also ran across the country, through Sacramento, to points east. Today, however, it ends in Crockett. Thanks to Ereneta for correcting my earlier mistake, thinking it still went to Sacramento, that was based on 40-year old information.
Places it passes through in the bay area with points of interest that I know of (from north to south):