Lava flow at Hawaii Volcanoes National Park, Hawaii

Moose at Grand Teton National Park, Wyoming

Grand Canyon National Park, Arizona

Assateague Island National Seashore in Maryland and Virginia

Bryce Canyon National Park, Utah

Acadia National Park, Maine

Glacier National Park, Montana

Canyonlands National Park in Utah

Hall of Mosses at Olympic National Park, Washington

White Sands National Park in New Mexico

Niagara Falls National Heritage Area, New York

Everglades National Park, Florida

Yosemite National Park, California

Arches National Park, Utah

Gettysburg National Military Park in Pennsylvania

Great Smoky Mountain National Park (Tennessee and North Carolina)

Giant sequoia trees in Sequoia and Kings Canyon National Park, California

Cape Hatteras National Seashore, North Carolina

Haleakala National Park, Hawaii

Badlands National Park in South Dakota

Virgin Islands National Park, U.S.V.I.

Crater Lake National Park, Oregon

Saguaro National Park, Arizona

National Mall, in Washington, D.C.

Isle Royale National Park, Michigan

Denali National Park & Preserve, Alaska

Big Bend National Park, Texas

Zion National Park, Utah

Death Valley National Park, in Nevada and California

Carlsbad Caverns, New Mexico

Gulf Islands National Seashore