This trail is essentially an attempt to have a continuos trail around the entire circumference of the San Francisco Bay. It has been a long term project to say the least and is still not complete as of this writing, though you'd be surprised at how much of it is in place. Great for birdwatching as the marshlands are home to many species both permanent and migratory (low tide is best). Also a close-by chance for some "ocean air" without having to commute "over the hill".
For more info on this trail go to my hiking website at:www.HikingTheBayArea.weebly.com.