Post your guesses in the comments section below.
Guess correctly and be crowned "Castro Valley know-it-all" for the week.
Congratulations to for correctly guessing . The free dirt sign sits in front of a private house off Stanton Avenue.
Thank you to Jim Uhlik for supplying this week's photo.
Have your own photos around town that you'd like featured in our Castro Valley photo challenge? Send them to email@example.com and see if you can stump our readers!