Dogtown is a deserted colonial settlement in the middle of Cape Ann, Massachusetts. eGuide Dogtown shows a users location as he or she walks along the old roads and trails of Dogtown, along with placemarks along the way. Placemarks mark the location of cellar holes - the root cellars of colonial houses, Babson boulders - more than two dozen word rocks scattered across the landscape, and other natural and cultural features. Tapping a placemark provides a text description of the feature. In effect the app functions much like a trail guide or docent at a museum, without need of any other external device other than an iPhone.