Considering that walking in nature calms us and even changes our DNA for the better, Nature World News is keeping an eye on opportunities to walk in greenery in all North American cities. Recently, we walked a relatively urban but lovely trail from near downtown Portland, Maine to Mackworth Island, which is next to the suburban town of Falmouth and is the mostly wooded home of a 1.25-mile perimeter trail and the former Baxter School for the Deaf.

The journey to Mackworth Island is a great walk or bike ride of about 4.5 miles each way. You'll start on Baxter Boulevard across from Hannaford Supermarket on the Back Cove Trail. This is a pleasant, wide path past an estuarial cove in Portland's north side. You'll see houses across the water, but on your side you will see signage for rain gardens (greenery that we can plant to soak up rain and prevent flooding) and other park features. Take the trail east toward the bridge crossed by Highway 295. After crossing this bridge using the designated pedestrian/bike area, walk maybe a half mile and look for Veranda Street, then hook a right on that. (Scroll down to continue...)

All in all, a walk or bike ride to Mackworth Island is pretty amazing--it's one of the rare occasions in U.S. cities when one can walk or bike for five miles or more on designated paths and without traffic hassle. The town of Falmouth also has a high-quality designated walk/bike trail along Highway 295, its central thoroughfare.

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-Follow Catherine on Twitter @TreesWhales