The Walden Street Cattle Pass, also referred to as the cow path, is an historic site adjacent to the MBTA Commuter Rail Fitchburg Line right-of-way, under the Walden Street Bridge in Cambridge, Massachusetts. It was added to the National Register of Historic Places in 1994. Don't forget to check out our Kickstarter Campaign! If you love Curionic pledge what you can! Even a dollar and a share helps!