Post your guesses in the comments section below.
Guess correctly and be crowned "San Lorenzo know-it-all" for the week.
Congratulations to for being the first to correctly guess . The rock fountain can be found at the little league park off Grant Avenue.
Have your own photos around town that you'd like featured in Castro Valley Patch's photo challenge? Send them to firstname.lastname@example.org and see if you can stump our readers!