The Empty Interior
Pittsburgh is located near many beautiful state state parks and national forests  that offer many beautiful scenic hikes. One of the largest National Forest in the Pittsburgh ares is Allegheny National Forest. It is located in northwestern Pennsylvania and is over a half a million acres. Within the the forrest is the Allegheny Reservoir and Kinzua Dam. The Allegheny Reservoir is between the Pennsylvania and New York border. 


Sources:
http://pittsburgh.about.com/od/day_trips/p/alleg_forest.htm   
http://photo.accuweather.com/photogallery/2009/10/500/6f8f297df.jpg