Valley Forge National Historical Park Fade to Purple Underground Visitor Center Juvenile Northern Mockingbird Winter Huts at ValleyForge Bunks in the winter cabins Cannon at Valley Forge Valley Forge Station George Washington Washington's Headquarters Washington's Headquarters Mexican Mallard x Northern Mallard Hybrid Bosque del Apache National Wildlife Refuge Sandhill Crane Ross's Goose Gambel's Quail Harris's Sparrow Eastern Phoebe A Mountain of Sandhills Bewick's Wren Phainopepla Canyon Towhee Bushtit Bison Tallgrass Prairie National Preserve Eastern Meadowlark Tallgrass Prairie National Preserve Warbling Vireo Bonaparte's Gull Field Sparrow Indigo Bunting Fish Crow Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Elisha_A_Hancock_005 Common Nighthawk (Chordeiles minor)