America's 63 national parks protect over 84 million acres. Top 15 to visit: 1) Yellowstone (WY) — geysers and wildlife, 2) Grand Canyon (AZ) — South Rim views, 3) Yosemite (CA) — granite domes and waterfalls, 4) Zion (UT) — Angels Landing hike, 5) Glacier (MT) — alpine lakes, 6) Acadia (ME) — rocky coast, 7) Grand Teton (WY) — Teton Range, 8) Olympic (WA) — rainforests and beaches, 9) Rocky Mountain (CO) — Trail Ridge Road, 10) Bryce Canyon (UT) — hoodoos, 11) Arches (UT) — natural arches, 12) Great Smoky Mountains (TN/NC) — most visited, 13) Crater Lake (OR) — deepest US lake, 14) Joshua Tree (CA) — desert and rock formations, 15) Denali (AK) — Mt. Denali. Get America the Beautiful pass ($80/yr) for unlimited access.