Moon over Pinnacles; Pinnacles National Monument, California

Sage Creek Wilderness Area; Badlands National Park, South ...

Pictographs on wall of Painted Cave, San Marcos ...

Detail of catlinite cliff; Pipestone National Monument, Pipestone, ...

Composite of moon, trees and human effigy, Bannock ...

Bison and fire-swept slope; Yellowstone National Park, Wyoming

Echo Canyon; Zion National Park, Utah

Cliff face, Cable Mountain; Sion National Park, Utah

Erosional formations; Bryce Canyon National Park, Utah

Cliff palace and cliff face; Mesa Verde National ...

Moonrise Over Bryce; Bryce Canyon National Park, Utah

Petroglyphs in sunset light; Jeffers Petroglyph Site, Jeffers, ...

Boulders and trees; Ringing Rocks State Park, Pennsylvania

Lunar Necklace; Chaco Culture National Historic Park

Doors, Pueblo Bonito; Chaco Culture National Historic Park, ...

Detail of sandstone cliff at White House Ruins; ...

Wildflowers; Mount Shasta, California

Shoreline at Goat Rock; Bodega Bay, California

Sky Hole; Mount Shasta, California

Report to the Secretary of State, Canada and ...