U.S. National Parks Service at 100 Years

Washington's Headquarters at Valley Forge National Historical Park in Valley Forge Pa., Thursday, April 3, 2008. (AP Photo/Matt Rourke)

By Zack Tanner / Pittsburgh Post-Gazette

Washington’s Headquarters at Valley Forge National Historical Park in Valley Forge Pa., Thursday, April 3, 2008. (AP Photo/Matt Rourke)