ANCIENT RUINS
Sites from the mound builders of the archaic-woodland and Mississippian Culture in the east to the numerous, well preserved cliff-dwelling ancestral puebloan ruins and Great Houses of the U.S. Southwest
BRIDGES
Historic and modern structures of varying styles, spanning rivers and streams, canyons and gorges, and mountain cliffsides for the purpose of transporting vehicles, trains, or pedestrians
BUILDINGS AND CITYSCAPES
Highlighting some modern human utilitarian constructs from pastoral barns to coastal lighthouse keeper residences to towering city skylines
DAMS
Constructed barriers along rivers of the United States, often commissioned by the Bureau of Reclamation with the goal of harnessing the water's energy and invaluable resource in the arid west
FORTS
Walled fortresses fortified with defensive structures, such as watch towers, ramparts and moats, and parapets from which canons and military armory can be positioned
HISTORIC SITES
Areas and structures representative of historical events, time periods and movements, such as those of expeditions and explorations, missionaries, mining ghost towns, pioneering homesteads, and affluence spas
INDUSTRIAL SITES
At the edge of preserved natural areas, a few of the signs of America's industry, including hydroelectric power plants and oil refineries
LIGHTHOUSES
Towering, guiding beacons rising high along coastal water ways of the Atlantic and Pacific oceans and the shores of the Great Lakes, marked with their own signature patterns and styles of identification
MEMORIALS
Carvings, sculptures, and edifices constructed to honor historical figures, events, and fallen heros
ROCK ART AND WOOD CARVINGS
Inscriptions of traveler's names and date of visitation; Artwork depicting symbols, human figures, ceremonies and traditions along with revered animals etched or painted onto wood and stone by past and presen
TRANSPORTATION AVENUES
Roads and railroad tracks leading through natural, wild environments
WINDMILLS AND FENCES
Old fashioned and modern style windmills and fencing built across the American west landscape
